Thanks for reply , We are using Zimbra mail server (IMAP) for all our mantis old and new . Old Mantis : Mantis BT version : 1.2.17 and Email Reporting : Email Reporting 0.9.0-DEV which is working fine without any issues on same Mantis server.
I have install Matnisbt 2.4.1 and Email reporting 0.10.0-DEV but it is not working , I have other mantis Old versions on same server and that is working fine.