My customer had a startalk A that was dying, they wanted to upgrade so I offered a NAM 4.1. I have installed the voice mail and all was okay until they started noticing that sometimes they would hit the voice mail transfer key (F986)and the call is returned to their set immediately. They are unable to transfer a caller into voice mail. I have gone through removing all of the feature codes associated with voice mail, restarted the system, still the problem returns. I also busied all the ports to verify the ports are working. Any ideas? Thanks..

Paul.
What Rel. have you replaced? If your software on MICS older then 4.1 you are going to have a problem. You have to make sure that NAM Rel is compatible with your MICS Software Rel. With NAM it is not so simple.

According to Nortel NAM 4.1 is compatible with any Software of MICS. So I was wrong.
make sure you are using only one pair per port and customer is not using (F986) w/Int. Autodial. has to be F986 and dialing the Int. number. Besides that MB has to be existing Ext# but not a virtual.

It can be any valid initialized mailbox (real or phantom) and as vad60 has said user must dial the MB number you can't use a DSS key (this is a common error).

The problem is that when they dial F986, the call immediately returns, and you can't put the caller into any VMB.