AzureAAD SSO giving Exchange error from central endpoint

One user is getting this when hotspotting from his phone, I can’t find anything that gives me a clue to what is going wrong. Any ideas?

Hi there, I have the same issue but with two users. Need help!

Have determined this user left the VPN connected when leaving his home office and when he got to site he hotspot to his 4G, it seems ZT doesn’t handle the laptop sleep/wake at new IP service. Restarting the ZT service seems to resolve the issue for him this time.