Need some assistance troubleshooting a Unity 5.0 Voice Mail to Nortel Option 11 (Succession4 software) with a Cisco 2821 Gateway with IOS 12.3(14)T4 and QSIG on the T1 interfaces. All is working now but everu time a voice mail is left on the Unity for a user on the Nortel side, the MWI on/off signal generates a PRI#265 error on the Nortel system. There are over 1000 of these error messages per hour. The errors don't SEEM to cause any detriment on either system other than a pain in the ... for the customer's help desk. Has anyone else run into this situation and how did you resolve the issue. Will be scheduling time on the customer router to perform some "isdn q931 debug" to try to identify the code that the Nortel is unable to identify correctly. Am searching on my Nortel side to resolve issue as well but wanted to also see what the Cisco side had to say. Customer implemented via IP only and QSIG with no external serial interfaces for the MWI control. Any suggestions?