pyramid middleware call to mssql stored procedure - no response
The solution was rather trivial. Within one object instance, I was calling two different stored procedures without closing the connection after the first call. That caused a pending request or so in the MSSQL-DB, locking it for further requests.
From a pyramid middleware application I'm calling a stored procedure with pymssql. The procedure responds nicely upon the first request I pass through the middleware from the frontend (angularJS). Upon subsequent requests however, I do not get any response at all, not even a timeout. 
If I then restart the pyramid application, the same above described happens again.
I'm observing this behavior with a couple of procedures that were implemented just yesterday. Some other procedures implemented months ago are working just fine, regardless of how often I call them.
I'm not writing the procedures myself, they are provided for. 
From what I'm describing here, can anybody tell where the bug should be hiding most probably?