If you are having MWI issues on Avaya Aura Messaging here is the procedure to resync Cache from the MAS. It will affect voicemail funcitionality so best to do out of hours unless you have permission from customer.
Login to server > Administration > Messaging > Advanced (Application) > System Operations
Reload Caches > Application Distributed Cache (ADCS): Synchronize
Now retest …
If this does not resolve then carry out the following;
Local Directory Cache (Clear the local directory cache) > Clear Distributed Cache (ADCS) Maintenance > General
a. Delete Cache
b. Clear Cache.
c. Clear Greeting/Names.
Reload Caches > Application Distributed Cache (ADCS): Synchronize
