You may want to refresh or suppress message waiting indicators. Reach the Suppress/Refresh MWI menu from the Main Menu by selecting (S) System Maintenance, (R) Reconfiguration, then (C) Suppress/Refresh MWI.
At the Suppress/Refresh MWI menu, you can set parameters to refresh some or all message waiting indicators, suppress message waiting indicators for specific MWI types, and view the current MWI types and settings. When you set the first and last mailboxes, be sure that the range is no more than the maximum of 2400 mailboxes.