We have a customer who is having problmes with text-to-speech on the Unity server. The version of Unity is 4.0(5). If you stop and restart the Unity service, the problem is resolved. This has been happening every few weeks.
When a user checks their messages from their phone, Unity will tell them how many voice and email messages they have but it won't read the emails. When trying to read an email, the system says: This message can not be read at this time. Please try later.