I am unable to send outlook mail from my mac.

Hi daisybell8,

To clarify, is this using the Outlook app for Mac or the standard Mac Mail app?

If it is in Mac Mail, double check the tips here, especially the results of the Connection Doctor.

• If you can’t send emails in Mail on Mac - Apple Support

"If you can’t send emails in Mail on Mac

In the Mail app  on your Mac, if the Send button  is dimmed in the toolbar of your message, or your message can’t be sent using the outgoing Mail server, try these suggestions.

• Make sure the outgoing (SMTP) mail server is specified as directed by the provider of your email account. See Verify an email account’s outgoing server.
• Choose Window > Connection Doctor, then follow the instructions displayed in the Details column.
• If there’s a firewall problem, verify that firewall software isn’t blocking email traffic on port 25, 465, or 587. Also check whether you’re affected by another firewall, such as software installed separately from macOS or built into an internet sharing router, or administered by your email account provider. Contact the appropriate person for information.

You may be able to send messages from only a certain location, or your email account provider may have stricter settings for sending messages (such as requiring a name and password). Contact your provider, then change the outgoing mail server settings in Mail settings as needed."

Should the issue persist from there, or you're using the Outlook app for Mac, we'd advise contacting Microsoft directly for support with their service.

• Microsoft Support

Cheers!