ORA-12516 : TNS :Listenercould not find available handler with matching protocol stack (LDAP)

Issue:

We are not able to login to the DB DEV_CN_ENTERPRISE_APP
and when we try logging-in we are getting the below error:

Error Message: ORA-12516 : TNS :Listenercould not find available handler with matching protocol stack
DB: DEV_CN_ENTERPRISE_APP
Schema: CN_ENTERPRISE

Resolution :


Steps

- Check Sessions connected / Processes (count)
- Check database Parameters for sessions / processes Configured
- Check Service is Up and Running
- Check Listener Value & Status in Database and OS
- Check LDAP Entry for the service
-Possibly it is because the Differnet Host details in Listener & service Configuration
- remove Old Serrvice & add New LDAP entry with correct Host details (logical Host in RAC)

sample to add LDAP in Unix


oracle/local/dba/bin/ogb_ldapadd.pl -d PRODT010_ADHOC_LOPR -h glbl002400-vip.eu.hedani.net,glbl200131550-vip.eu.hedani.net,gbl20013156 -R 

where -d is service name

-h is the scan name for example PRODD2047-scan.eu.hedani.net

and -R means RAC

there is also 

ogb_ldapsearch.pl -s for searching, 

use * for all string i.e. ogb_ldapsearch.pl -s PRODT0* and of course ogb_ldapdelete.pl for removing service form ldap