license issues can produce an authenticationError when retrieving a user's inbox. This catches that error and treats it as a "mailbox not availble" condition.
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#### Does this PR need a docs update or release note?
- [x] ⛔ No
#### Type of change
- [x] 🐛 Bugfix
#### Issue(s)
* #3743
#### Test Plan
- [x] ⚡ Unit test
- [x] 💚 E2E