Question: Why is this error showing up? the error says "InvalidOperation: The connection was not closed. The connections current state is connecting".
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Answer: This error is thrown by Entity Framework (EF Core), if you see in the Stack Trace log, you can notice that the Microsoft.Data.ProviderBase.DbConnectionClosedConnecting.TryOpenConnection() function threw this exception.
In order to resolve the issue, just stop debugging the application and restart again. I hope this helps you, if it does please leave a comment below indicating how you solved the error.