Question: Mail Issues with High Sierra
Upgraded my 2011 iMac to High Sierra, now having Mail problems. Was running OS X Lion 10.7.5, in order to upgrade to High Sierra, first needed to upgraded to OS X El Capitan 10.11.6 then to macOS High Sierra 10.13.1. Now that I'm at High Sierra, I'm having Mail issues. I have 3 address. All worked fine prior to the upgrade. After the upgrade, none worked. Kept getting a message stating accounts are off line. I would try going in and to put the accounts back on line but it would not work. So I tried to just re-add the addresses as if they were new and that worked for two of them. The third did not. So after trying several times I deleted the address that was not working and tried to re-add it. When I try to re-add the address a message comes up saying "This account already exists". Is there anyway to get the account back up on Mail? Thanks.
iMac, macOS High Sierra (10.13.1), 2.7 GHz Intel Core i5, 4GB