cannot create email account for outlook in mac email client

If Mail on your Mac keeps asking for your password

Using app-specific passwords and check if Outlook mail has setup similar requirements as Apple does for Third Party Applications getting access to iCloud.

Many eMail providers now require a separate App Password different from your eMail password…

Then you may need Ways to securely access AOL Mail…

https://help.aol.com/articles/allow-apps-that-use-less-secure-sign-in

May just need an App Password...

https://support.google.com/mail/answer/185833?hl=en-GB

Yahoo has gone to this too...

https://help.yahoo.com/kb/access-yahoo-mail-third-party-apps-sln15241.html

Yahoo App password…

Generate and manage third-party app passwords

Some older, third-party email apps (that do not use our Yahoo branded sign in page) require you to enter a single password for login credentials. To access your Yahoo Mail account on these apps, you'll need to generate and use an app password. An app password is a long, randomly generated code that gives a non-Yahoo app permission to access your Yahoo account. You’ll only need to provide this code once to sign in to your third-party email app.

https://help.yahoo.com/kb/access-yahoo-mail-third-party-apps-sln15241.html

Using app passwords with apps that don't support two-step verification (microsoft.com)

Try setting up the account in the Internet Accounts System Preferences.

When you say Outlook email I assume this means a MS-Exchange email account. Exchange is listed as an option in the Internet Accounts System Preferences. If the account is already listed there, try entering the password from the System Preferences Internet Accounts pane. If it still returns with an error (cannot verify), try clicking on the "Details" button for that account and enter the password there. I have seen that "cannot verify" error message also but have always been able to succeed in entering the password from the "Details" button. I have done this on Macs running El Capitan, High Sierra, and Catalina ... I don't have any right now with Mojave but I think the steps are very similar or the same.

Great news, take care my friend! :)