Artie is probably correct that simply waiting a while will "fix" you email problem. As to changing the password. Apple Mail, Apple iCloud, Apple App Store, and iTunes all use the same
Apple ID and password. If you change one — all are changed. The Apple ID password can
ONLY be changed via the internet but you can access it via...
- System Preferences > iCloud Account Details
- iTunes > Account > View My Account
- App Store > Store > View My Account
- logging on to iCloud and going to Settings > Apple ID > Manage
It is not accessible via terminal.
Your computer account ID and password are independent of the Apple ID and password (except you can choose to allow your Apple ID and password to unlock your computer account). Your computer account password can be changed in
- System Preferences > Accounts
NOTE:If you have two step verification turned on changing either password will require you verify the change through another device registered to your Apple account.
When you get a request for a userid and/or password read the request carefully as it is very easy to get confused about which one is being requested.