Trying to set up MAC mail - SMPT server wont accept login
Are you using a mobile device? Or a desktop?
If you are using a desktop, try settting up the un-authenticated outgoing server,
If you are usnig a device that travels (tablet, phone, laptop) log into Webmail, Preferences, General, Mobile Devices, and check your password, making sure it passes, then click Save.
After that, if it still doesn't work, please post your outgoing server settings that you are using.
If you are using Apple's Mail, try turning off "Organize by Conversation" in the View menu. Delete your smtp server and get rid of any emails sitting in your Outbox. Quit Mail, restart it and set up the smtp server again using shaw's directions. When Organize by Conversation was enabled I found Mail was holding on to old settings that affected the smtp server. I was getting odd behaviour: password requests, smtp server not responding or just a quick blip in the Activity window and then it sat in the Outbox. Getting rid of that setting was what got it working for me.
Another thing that could affect it is getting rid of your own email in the "Previous Recipients" found in the Window menu. I was told that this has worked too.
We also have a great document set up at How to set up email in Apple macOS Mail that will let you know all the settings that you will need. It's possible that one of the SMTP settings is incorrect.
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