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SqlException: A connection was successfully established with the server, but then an error occurred during the login process

I upgraded my WebApi project from NET6 to NET7. I use EF Core 7 in my project.
I knew that there was a breaking change involving SQL Server and certificates. So I changed my connection string in the project's appsettings.json to:
"ConnectionStrings": {
"DB": "data source=myserver;initial catalog=mydb;MultipleActiveResultSets=True;App=MyApp;Trusted_Connection=True;TrustServerCertificate=Yes;Encrypt=false;"
}
I added Trusted_Connection, TrustServerCertificate and Encrypt to test if the connection will work.
The website was published to IIS (where the ASP.NET Core Runtime 7.0.0 is installed).
However I'm getting the following exception on a GET request:
SqlException: A connection was successfully established with the server, but then an error occurred during the login process. (provider: SSL Provider, error: 0 - The certificate chain was issued by an authority that is not trusted.)
And the following on another GET request:
{"type":"https://tools.ietf.org/html/rfc7231#section-6.6.1","title":"An error occurred while processing your request.","status":500,"traceId":"00-f7ac7c853fbfe3ef43a3d8b567fadbdb-a30b994f51839fcb-00"}
The above changes to the above connection string should have fixed this problem. But the problem persists and I don't know that else I can change to get the website to work again.
The SQL Server either has a self-signed certificate or no certificate at all. All I need is to get the code to work with the current setup.
What am I missing?

EF Core understanding migrations

I encountered some weird behaviour with EF Core 3.1 that made me wondering what is actually happening. So hopefully someone can explain this to me in all fine details.
Scenario
Let's say you have two projects. Project A (main) and project B (side-project). For both projects you can add/remove migrations, as project A is set-up to get all pending migrations from project B on start-up and execute them.
When executingdotnet ef migrations add Test -c AppDbContext -o DbContexts/Migrations/AppDb on project A and after completion (BEFORE even applying it to the DB) execute dotnet ef migrations remove -c AppDbContext, everything works as expected and the migration gets removed.
For project B on the otherhand after succesfully executing the add command, the moment that I try to execute the remove command (also BEFORE even applying it to the DB), I get the following error:
Microsoft.Data.SqlClient.SqlException (0x80131904): A network-related
or instance-specific error occurred while establishing a connection to
SQL Server. The server was not found or was not accessible. Verify
that the instance name is correct and that SQL Server is configured to
allow remote connections. (provider: Named Pipes Provider, error: 40 -
Could not open a connection to SQL Server)
So I took the error message as an advice and started to follow this guide to allow remote access to the database. After the guide, the remove command on project B was also successfully executed.
But now I am wondering... Why wasn't EF Core connecting to the (LOCAL) DB before I followed the guide and DID it work on project A, but not on B....?
EDIT
After some more research, I discovered the specific action from the guide that helped me to resolve the error that I got. It was to set the TCP Port to 1433 in the Sql Server Configuration Manager. Apparently this field was empty... But it leaves me with 1 question.
Why did the add command DID work without a port specified and was only the remove command complaining about the connection?
EDIT2
And yet another new finding, when adding the following method to the AppDbContext class:
protected override void OnConfiguring(DbContextOptionsBuilder options)
{
options.UseSqlServer("foo");
base.OnConfiguring(options);
}
The add command works fine, but the remove command complains about the incorrect format of the connectionstring
System.ArgumentException: Format of the initialization string does not conform to specification starting at index 0.
So we can conclude from this that the add command DOESN'T require a valid connectionstring (as it does nothing with the DB), while the remove command DOES require a valid connectionstring... but why??? It does nothing with the DB, right?

As an answer to my own question, here an explanation on how the add and remove migrations work.
The add migration functionality DOES require a valid string as the connectionstring in the context, but it DOESN'T need to be a correct connectionstring, as EF Core is not realy connecting to the DB.
For the remove migration functionality, you DO require a correct connectionstring, as EF Core makes a connection to the DB to compare the local list of migrations with the _EFMigrationsHistory table to check if there are any migrations that has not been applied to the DB. Because the remove functionality can only remove PENDING migrations. So not any migrations that have already been applied to the DB.

EF core Scaffold-DbContext doesn't work : Execution Timeout Expired

I'm trying to scaffold Models from an existing database.
Scaffold-DbContext "connectionString" Microsoft.EntityFrameworkCore.SqlServer -OutputDir Models
But I got this error:
Microsoft.Data.SqlClient.SqlException (0x80131904): Execution Timeout Expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
All required packages are installed (tried another connection string and it's working)
Tried (Connect timeout 15000 and Connection timeout 15000)
I can connect with the same connection string via Sql Server management / VS Server explorer
Any ideas?

As far as I know there is no solution at the moment.
The SQL Server connection string does not allow to define the command timeout, but only the connection timeout.
I solved it using the --schema dbo option, which eliminated a dozen tables that have another schema, and now it works.
But for how long?
My code:
dotnet ef dbcontext scaffold "SERVER=.;DATABASE=dbstore0;Integrated Security=SSPI;Connection Timeout=300;TrustServerCertificate=True" Microsoft.EntityFrameworkCore.SqlServer -f -o DbStore\Models --context-dir DbStore\Contexts -c DbStoreContext -p Store.Domain.csproj --no-pluralize --schema dbo

For me, it worked with SQL Server 2019 (15) by adding Command Timeout=300 to the Connection String.

Entity Framework Core Error: An error occurred using the connection to database '' on server 'localhost'

I have made an ASP.NET Core 3.1 Web-based application and want to use MySQL as the database.
I have been following along with some YouTube tutorials on creating MySQL database with ASP.NET Core 3.1 [code first approach] including a tutorial from this site:
https://learn.microsoft.com/en-us/aspnet/core/data/ef-rp/intro?view=aspnetcore-3.1&tabs=visual-studio
I have created a DataModel Class, added a service to UseMySQL to the Startup.cs Class and created an AppDBContext Class that implements DbContext Class.
When I run this command in the Package Manager Console: Add-Migration InitialDatabase the application is creating a migration successfully.
When I run update-database it is throwing this exception:
fail: Microsoft.EntityFrameworkCore.Database.Connection[20004]
An error occurred using the connection to database '' on server 'localhost'.
An error occurred using the connection to database '' on server 'localhost'.
System.InvalidOperationException: An exception has been raised that is likely due to a transient failure. Consider enabling transient error resiliency by adding 'EnableRetryOnFailure()' to the 'UseMySQL' call.
When I call the EnableRetryOnFailure(); function as required, I am facing this exception:
fail: Microsoft.EntityFrameworkCore.Database.Connection[20004]
An error occurred using the connection to database '' on server 'localhost'. An error occurred using the connection to database '' on
server 'localhost'.
What could be the issue?
Where am I getting it wrong?
If you have links to useful articles about using MySQL Database with ASP.NET Core I would appreciate or your help on this particular issue.
I am using Visual Studio IDE 2019 and ASP.NET Core 3.1.1
Additional Code:
This is the Startup.cs Class:
private IConfiguration _configuration;
public Startup(IConfiguration configuration)
{
_configuration = configuration;
}
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
services.AddControllersWithViews();
// database connection string configuration
services.AddDbContextPool<AppDBContext>(options => options.UseMySql(_configuration.GetConnectionString("DatabaseConnectionString"),
mySqlOptionsAction: options => { options.EnableRetryOnFailure(); }
));
services.AddMvc();
}
This is the connection string in appsettings.json:
"ConnectionStrings": {
"DatabaseConnectionString": "Server=localhost;Database=MyAppDB;user=root;Password=123;"
}

I think I found the root of the problem. This error also occurs when the connection to the database couldn't have been established. Make sure the information in your connection string is correct. This error message is very misleading, I spent couple of hours figuring this out because of it.

You can try this way
Install package Pomelo.EntityFrameworkCore.MySQL
Add services at Startup.cs
services.AddCors();
services.AddDbContext(options => options.UseMySql(Configuration.GetConnectionString("DatabaseConnectionString")));
change connection string at appsettings.json
"ConnectionStrings": {
"DatabaseConnectionString": "server=localhost;port=3306;database=MyAppDB;user=root;password="
}
*change the port number according to your MySQL server
4.Run these commads at Package Manager Console for data migration
Add-Migration InitialCreate
Update-Database
You can look at the project at github, for better understanding

In my case, I just added the database port separately.
changed this from
MySQL": "server=mysqlserver.com:3306;user=db_user;password=db_pass;database=database_name"
to
MySQL": "server=mysqlserver.com;port=3306;user=db_user;password=db_pass;database=database_name"

Your connection string doesn’t seem to be right or EF is not able to pull it. You ll need to check the docs and select the correct project before running the update.
Confirm the connection string using this post:
https://www.c-sharpcorner.com/UploadFile/suthish_nair/how-to-generate-or-find-connection-string-from-visual-studio/
You can try this workaround to specify the connection with the command, PS you ll need to update the provider name for MySql:
Update-Database -Verbose
-ConnectionString "CONNECTIONSTRING"
-ConnectionProviderName "System.Data.SqlClient"
-StartupProjectName WEBSITE_PROJECT -ProjectName MIGRATION_PROJECT

I had the same problem, this error occured the me when the connection string was wrong. In my case it was the port (by default 8457). Have you tried specifying it in the connection string?

Your steps don't seem to include installing a local instance of MySQL Server, which could be why you cannot find a server... because its not installed!
MSSQL (localdb) is bundled with Visual Studio 2019 (with the Data Modelling and Processing workload) but MySQL still needs to manually installed.
Have you tried installing a supported version of MySQL Server with your EF Provider?

I had the same problem. This error occured when a MariaDB and the web app runs on the same host.
A hint for a solution you can find here:
Now that your MariaDB server installation is setup to accept
connections from remote hosts, we have to add a user that is allowed
to connect from something other than 'localhost' (Users in MariaDB are
defined as 'user'#'host', so 'chadmaynard'#'localhost' and
'chadmaynard'#'1.1.1.1' (or 'chadmaynard'#'server.domain.local') are
different users that can have completely different permissions and/or passwords.
In my case a user mdbuser is allowed to connect from hosts 192.168.178.% according to the table mysql.user.
So I added a second user named mdbuser with localhost and the error disappeared:
GRANT ALL PRIVILEGES ON *.* TO 'mdbuser'#'localhost' IDENTIFIED BY 'password' WITH GRANT OPTION;

This also happens if you forget to specify the Connection String in case of using SqlServer in NET6:
Wrong:
var conString = builder.Configuration.GetConnectionString("MyDbConnection");
builder.Services.AddDbContext<MyDbContext>(options => options.UseSqlServer());
Correct:
var conString = builder.Configuration.GetConnectionString("MyDbConnection");
builder.Services.AddDbContext<MyDbContext>(options => options.UseSqlServer(conString));

Suffered same error on IIS 8.5. The connection string was wrong, fixed it but error still showed.
Solution: Recycle the app pool. Changing the .json file doesn't restart de app so you need to do it.
Hope it helps somenone.

In my case it was a permission issue with AWS RDS.
I had to add an inbound rule in the security group with my IP. I was then able to connect

Connecting database to .net core MVC project

It is my first time using .NET core 2.2 and MySQL workbench ,
I am trying to build a very basic website.
I followed the following Microsoft tutorial
https://learn.microsoft.com/en-us/aspnet/core/tutorials/first-mvc-app/working-with-sql?view=aspnetcore-2.2&tabs=visual-studio
After I added a Scaffolded item,I followed the instructions and opened the NuGet package manager and executed these commands in the cli:
Add-Migration Initial
Update-Database
The Update-Database command raised the following error :
A network-related or instance-specific error occurred while
establishing a connection to SQL Server. The server was not found or
was not accessible. Verify that the instance name is correct and that
SQL Server is configured to allow remote connections. (provider: Named
Pipes Provider, error: 40 - Could not open a connection to SQL Server)
I am working with a Bluehost (Shared Host) server, I modified the permissions so I could connect remotely to the database (and indeed I am connected through MySQL workbench)
I tried changing the ConnectionString to the following:
"ConnectionStrings":
{
"Piano3Context": "Server=162.241.*.*;Database=PianoDB;User Id=omyUsrName;password=myPass;Trusted_Connection=True;MultipleActiveResultSets=true;"
}
and yet I receive the same error.
If any other code will help please note and I will post.

The tutorial you mentioned is using and SQL-Server. For connecting to a MySql server you need a different database provider. You can install the Pomelo.EntityFrameworkCore.MySql nuget package for Mysql. See the providers page in the microsoft docs.
After that you need to change the options.UseSqlServer from the tutorial to options.UseMySql as described on the mysql providers project page.

In addition, this is how to set the options for MySQL, you can move the config string to the Configuration and use the GetConnectionString method.
services.AddDbContextPool<MvcMovieContext>(
options => options.UseMySql("Server=localhost;Database=ef;User=root;Password=123456;",
mySqlOptions =>
{
mySqlOptions.ServerVersion(new Version(5, 7, 17), ServerType.MySql); // replace with your Server Version and Type
}
));

I was beaten to it by #philipp-grathwohl you need to use MySql and configure that in your startup like his answer says.
You could use this command instead which Scaffolds the DBContext and Generates the EF models and Context in one command after you have changed the startup and added the nuget package Pomelo.EntityFrameworkCore.MySql:
Scaffold-DbContext "Server=<ip>;Initial Catalog=PianoDB;Persist Security Info=False;User ID=<username>;Password=<password>;MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;" Pomelo.EntityFrameworkCore.MySql -OutputDir Models -context Piano3Context -force
Do let me know if this last command spits out any errors.