ORA-12510: TNS:database temporarily lacks resources to handle the request?

Submitted by: Administrator
Cause: The dispatchers appear to be busy handling other
requests.

Action: Attempt the connection again. If error persists, ask
the DBA to increase the number of dispatchers and/or
dispatchers' limit on number of connections/sessions that
they can accept.
Submitted by: Administrator

Read Online Oracle Errors Job Interview Questions And Answers