Workflow Mailer service error- java.lang.NullPointerException

 In Oracle Apps R12.2.9, when configuring Workflow Mailer service, we got beow error 

1617826424396:-1:-1:xxxxxxxxxx.com::-1:-1:1:20420:SYSADMIN(0):-1:Thread[BES Dispatch Thread,5,main]::26197:1617826424309:24:ERROR:[SVC-GSM-WFMLRSVC-411183 : oracle.apps.fnd.cp.gsc.SvcComponentContainer.onBusinessEvent(BusinessEvent)]:java.lang.NullPointerException

        at java.util.Hashtable.put(Hashtable.java:514)

        at oracle.apps.fnd.wf.mailer.Mailer.validateParameterValues(Mailer.java:874)

        at oracle.apps.fnd.cp.gsc.SvcComponent.performValidateParameterValues(SvcComponent.java:233)

        at oracle.apps.fnd.cp.gsc.SvcComponent.start(SvcComponent.java:314)

        at 

oracle.apps.fnd.cp.gsc.SvcComponentContainer.handleComponentEvent(SvcComponentContainer.java:2223)

        at oracle.apps.fnd.cp.gsc.SvcComponentContainer.onBusinessEvent(SvcComponentContainer.java:301)

        at oracle.apps.fnd.wf.bes.DispatchThread.run(Unknown Source)

Resolution

First issue was with the imap account password and we reset the same.

Second issue was solved following Doc ID 242941.1. The issue was with imap server. 

Figure out issue using below command. 

The connection was getting closed on the new  server while it was giving a "OK CASP01 IMAP4 Ready" message on old server.

New Server

$ telnet imap.xxxxx.com 143

Trying xx.xx.xx.xx...

Connected to imap.xxxxxxx.com.

Escape character is '^]'.

Connection closed by foreign host.

Old Server

$ telnet imap.xxxxx.com 143

Trying xx.xx.xx.xx...

Connected to imap.xxxxxxx.com..

Escape character is '^]'.

* OK CASP01 IMAP4 Ready