Apple Mail not accepting Outlook password on iMac (21.5-inch, Late 2012) running macOS Catalina - version 10.15.7

Hello

We are unable to add our Microsoft Outlook accounts to Apple Mail as each time Apple Mail rejects our Outlook password (despite it being correct) and displays, 'Unable to verify account or password'. Despite several attempts, we remain unable to add our Microsoft Outlook email accounts to Apple Mail. We have also cleared the Keychain of any potential password conflicts and this has not made a difference.

We are using an iMac (21.5-inch, Late 2012) running macOS Catalina - version 10.15.7. Even though we are using an older iMac we do not believe this is the problem.

Any suggestions on how to resolve this issue would be much appreciated.

Many thanks