The basic symptom you show implies that one or more applications using that
datasource have taken all the connections out of the pool, and have not yet
returned them for re-use. This is often an application thread-safety or code-path
problem where the connection they get is either overwritten by another thread,
or the reference to the connection is lost before it is closed. This is a 'leak'.
If you turn on WebLogic leak profiling and set an idle-connection-timeout setting,
the pool will retract those lost connections making them available again, and
also show you where in your code you would need to check for the leak.
No resources currently available in pool ePayBatchDS to allocate to applications.
This exception cleaarly shows the connection are not available to allocate to ePayBatchDS datasource.
As you said there are altogether 7 data source out which six are working and one is not.
In general if you are creating a datasource and providing a connection pool size we should consider the number of connection available or allowed at the database side as well.
Please cross check at the DB side the number of connection available and based on that try to tune the connection pool size in your data sources.