iPhone13C2 = iPhone 12 Mini (?) iPhone13C3 = iPhone 12 Pro iPhone13C5 = iPhone 12 Pro Max. iOS devices unfortunately do not register with ActiveSync or other tools with a logical clear human readable version number.Just change the “Mail Days to Sync” field to “No Limit”. Reset Network settings via Settings -> General -> Reset -> Reset Network Settings. Go back all your mail accounts and reset password.
