Before to restart, just take a look at your task manager if an instance of HonnorBuddy is still running.
If not (or you killed all instance of HB), and you have a "Max Session" error then :
- just wait the server to cancel the last session you used (1 or 2 minutes)
or
- go to Home Page - Buddy Auth Portal , connect to your account (or create one with your key), so cancel the current session.
I have resolved that issue buying more session than I use (ex : a 2 session key for 1 session running)