ORA-12516, TNS:listener could not find available handler with matching protocol stack

Hello All,

On one of our Prod server application team while trying to coonect got below error:

 

ORA-12516, TNS:listener could not find available handler with matching protocol stack

The issue was resolved on its own after some time. So it looks we reached threshold on sessions OR processes limit and once the count went down issue was resolved.

Now the catch here is we do not see this error captured in the alert logs.

Is there a way I can check on the max. numbers of sessions or processes that we hit during the time the issue was reported?