Created attachment 222650 [details]
This is a fix for an upstream bug. Given the level of activity on the snmptt Sourceforge project, I expect some delay until upstream fixes the bug.
The code attempts to change from the executing user to a configured service user, but it does this by first changing effective, then real uid.
It then briefly looks around curiously before falling flat on its face because the real uid change failed, the process not having root anymore at that point.
The attached patch reverses the order of the operations.