Good morning all, I'm on day 27 of trying to assist our VOIP person with a single user account that is giving issues with Single Inbox messages. Out of all the users we service this single account is throwing an error that I can't figure out. Please see the below image for the error.
Cisco provided our VOIP person the Microsoft Remote Connectivity Analyzer and the settings to use. When attempting to complete a test with those settings, the tool returns that it can find the account, but it can't create a new item and Error Mailbox Configuration: <nothing>. The weird thing is if I change the test to use user principal name instead of SMTP, it works and something triggers so the user will start getting voicemails. After testing with user principal name and switching back to SMTP the test will run successfully against SMTP instead of failing. This is where I'm at the head scratching part. It'll stay fixed for a little while, 30 minutes maybe an hour or two, then revert back to not working.
I've checked from my side (365) and the user name and smtp match as they should. I can find her seven ways to Sunday. There are no conflicting accounts. Does anyone have any possible suggestions as to why this account is doing this or what may be triggering the 365 sides connection to work suddenly?
![MicrosoftTeams-image.png MicrosoftTeams-image.png](https://community.cisco.com/t5/image/serverpage/image-id/145740i5BF359339E33B093/image-size/medium?v=v2&px=400)
![chrome_i0ok6vKEvz.png chrome_i0ok6vKEvz.png](https://community.cisco.com/t5/image/serverpage/image-id/145741i266395BF3DB72B05/image-size/medium?v=v2&px=400)