By default the snmpcollector database, (a file called snmpcollector.mv.db), runs in embedded mode and allows only one connection. If that connection to snmpcollector fails, it does not allow another.
It's possible to see errors like:
/opt/nimsoft/probes/network/snmpcollector/SnmpCollector.mv.db failed; file length -1 read length 32 at 184866602
The Snmpcollector log can have stack traces with errors like IllegalStateException and a cause of ClosedChannelException