On iPhone OS based devices, when viewing the meeting invitation in the calendar or the mail application, the sender may display as "unknown." This typically happens when using GroupWise or Meeting Maker as the mail/pim server. 

In addition, if a device is running iOS 4, the calendar application malfunctions when opening if there is an unaccepted meeting invitation and the mail application malfunctions when viewing meeting invitation details.

This issue is fixed with the application of GO!NotifyLink Enterprise Server (NLES) 4.6.2, Patch 18. 

End users who upgraded their iOS version prior to GO!NLES official support  for iOS 4 (Patch 18), will need to clear existing meeting invitations from the device Inbox and calendar or re-register the device to prevent malfunctions from continuing to occur.