Incoming mail server greyed out
Hi
Trying to change my incoming mail server on iMac, the option to do this is greyed out. When I go to advanced settings the 'Automatically detect and maintain settings' is greyed out too.
I have 3 email accounts, two of which are greyed out (from same server) the 3rd I can change (different server)
Any help would be appreciated.
Thanks
iMac, OS X El Capitan (10.11.2)