Question

I have an application that suddenly started throwing the following exception:

System.Data.SqlClient.SqlException: Login failed for user ‘username’.

The username and password are correct and the app does some queries/inserts using the same login before throwing the exception.

What are some other reasons a login can start failing? Does SQL Server have a default maximum number of connections that may have been reached? I’m using LINQ to SQL – does the fact that I’m reusing a DataContext to insert multiple rows of data rather than creating a new one each time have any relevant consequences?

Answer 1

I think the issue was with the way I was creating DataContexts – I was keeping one around in the class and creating a new method-local one every time I did an update (see here for more details). I just refactored the code to create a new DataContext for each transaction and the error went away.