Can not access Azure SQL database after moving Azure API app to custom domain

Question

I moved my API from free plan app service to a basic plan app service with custom domain and SSL certificate.

1) I see that my API app's status is "running", Authentication (AAD) is working properly

2) if I open it's api definition (i.e. */swagger/docs/v1) it IS working

3) If i try a request that does not try to access backend Azure sql db, then it is working correctly

4) If I use a request that call backend Azure SQL db (it worked before moving API to custom domain) it fails with this error:

{"The underlying provider failed on Open., StackTrace: at System.Data.Entity.Core.EntityClient.EntityConnection.Open()\r\n at System.Data.Entity.Core.Objects.ObjectContext.EnsureConnection(Boolean shouldMonitorTransactions)\r\n at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)\r\n at System.Data.Entity.Core.Objects.ObjectContext.<>c__DisplayClass651.b__63()\r\n at System.Data.Entity.Infrastructure.DbExecutionStrategy.Execute[TResult](Func1 operation)\r\n at System.Data.Entity.Core.Objects.ObjectContext.ExecuteStoreQueryReliably[TElement](String commandText, String entitySetName, ExecutionOptions executionOptions, Object[] parameters)\r\n at System.Data.Entity.Core.Objects.ObjectContext.ExecuteStoreQuery[TElement](String commandText, ExecutionOptions executionOptions, Object[] parameters)\r\n at System.Data.Entity.Internal.InternalContext.<>c__DisplayClass141.b__13()\r\n at System.Data.Entity.Internal.LazyEnumerator1.MoveNext()\r\n at System.Collections.Generic.List1..ctor(IEnumerable1 collection)\r\n at System.Linq.Enumerable.ToList[TSource](IEnumerable1 source)\r\n
at P..Repositories.DataAccessLayer.DbContexts.P..DbContext.GetP..Dtos()\r\n at P..Repositories.Repositories.P..Repository.P..Repository..ctor()\r\n at P..API.Controllers.A..Controller.Get()"}]}

Only thing I've found so far suggests that my API can not access Azure SQL because of firewall rules, but that doesn't sound as an option, since I just assigned a custom domain to my app, I believe it is in the same "place" in Azure... and I did not manage so far to find any suggestions regarding Azure SQL db connections when migrating API to custom domains...

Any ideas?

Answer 1

It turns out, that by some strange reason, after moving to custom domain - publishing settings, AzureDatabase connection string had a non-existent (seams like "generated" name -> Api name with added postfix _db) database name. When I changed it to the real db name, everything started to work again...

P.S. I guess unchecking "use this connection string at runtime (update destination web.config)" would give the same result, since web.config holds the right connection string.