Voicemail has been configured properly at Unity connection but when you press the ‘message’ button on the IP phone it just do nothing.
If you come across an issue like this then make sure you have Voicemail service configured under Device > Device Settings > Phone Services.
If it’s not there then you will have to run the following command from CUCM CLI:
admin: run sql insert into telecasterservice (pkid,Name,NameASCII,Description,URLTemplate,tkPhoneService,EnterpriseSubscription,Priority)values(‘ca69f2e4-d088-47f8-acb2-ceea6722272e’,’Voicemail’,’Voicemail’,’Voicemail’,’Application:Cisco/Voicemail’,2,’t’,1)