Messages from unidentified callers fail to be delivered

[shaunswales]

I am having problems with Unity 5, at first I thought messages at random were not being delivered. I confirmed connectivity etc with the partner mail server, and checked and reapplied rights with the permissions wizard, however messages still keep failing. In the logs, I see that only messages from unidentified callers were failing.

Which exchange account does unity use to send these messages to the subscribers?

subscriber to subscriber messaging works fine.

[shaunswales]

Found the problem.

Using DOHPropTest, I found that the path to the mailbox which unity uses to send messages from an unidentified caller, was missing, it had a value called: Error: 0x80072030.

I have logged a TAC case to get the password of the day, so I will change the value and monitor to see if this resolved the issue.