Hi @cshipley_6136 ,
We recommend using the /health monitoring endpoint. As you can see, it makes a connection to the database by calling that stored procedure.
We do not recommend calling other URLs; and there is no reason another page would work. Calling other pages will impact performance and likely yield incorrect results.
You're right, it might have to do with a "connection pool" problem -- but that's all managed at the driver level. You can control connection pool settings by changing connection string values, but to be honest we have no idea what the impact will be.
Your best bet is to open a case with Microsoft, who has the expertise to know how to troubleshoot these intermittent "error 40's". They may have specialized tools or "secret debugging commands" you can use.
This is all happening at the operating-system or driver-level, and while we're doing our absolute best to help you troubleshoot, but we have never seen this happen before and our main resource is searching google. And this is not an easy error to search for,..as you've probably noticed.
Please keep us in the loop.
Best,
Alana