Azure SQL user and connection string for Asp.Net MVC EF web app

I have an Asp.Net MVC webapp and I get the following error when I try to create a new Azure SQL user for the DefaultConnection.

[SqlException (0x80131904): Login failed for user 'myNewSQLuser'.]

On SQL Server Object Explorer I connected to the master database using the Server Admin login and I created a login for the new user with:

CREATE LOGIN myNewSQLuser WITH PASSWORD = 'myNewPwd';

Then with the same Sever Admin login I connected to the database corresponding to the webapp and created the user:

CREATE USER myNewSQLuser FROM LOGIN myNewSQLuser;

and then:

ALTER ROLE db_owner ADD MEMBER myNewSQLuser;

Then, on the web publish profile I have the following connection string:

Data Source=tcp:mydbserver.database.windows.net,1433;Initial Catalog=myAzureSqlDB;Persist Security Info=False;User ID=myNewSQLuser;Password=myNewPwd;Connect Timeout=30;Encrypt=True;TrustServerCertificate=False

When on Visual Studio, Edit Publish Profile, I am able to successfully test the connection string.

When I publish the MVC webapp to Azure App Service I see the "Login Failed" error mentioned above. However I am able to use the credentials for myNewSQLuser to connect to the database for example from Azure DataStudio.