System.InvalidOperationException

“Timeout expired” errors may be result of a wide range of issues such as network delays, application hangs, database locks. I have recently worked on an issue that was the result of ADO.NET database pool exhaustion.

The entire error message we captured in the DebugDiag dump file:

Exception Details

System.InvalidOperationException

Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached.

System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(System.Data.Common.DbConnection