SQL Loader intermittently throws "ORA-12516: TNS:listener could not find available handler with matching protocol stack"

I am running a weekly batch job which is loading data from txt/csv files to database using SQL Loader. But SQL Loader intermittently throws below error: > SQL*Loader-704: Internal error: ulconnect: OCIServerAttach
> ORA-12516: TNS:listener could not find available handler with matching protocol stack. As understood from similar posts, we have increased maximum number of sessions/connections limit which reduced the failure cases to lower side, but not totally resolved the similar issue. Do we also need to increase the maximum number of concurrent processes, as in the below screen shot I can see that oracle concurrent processes are exhausted? If not, please share your thought process if any other solution to the cause.