Hello togorman
Hi, I'm Karl and will be happy to help you today.
The only thing that is required to add an Outlook.com based email account (@Outlook @Hotmail @Live @MSN) to any version of Outlook desktop is entering the email address / password with the following caveat
The <Primary Alias> for the account must be an Outlook.com based email address
You can check your account alias addresses via this link
https://account.live.com/names/manage
Out of curiosity, did you install '2021 on the same machine as '2016? If yes, it would have used the same Outlook profile so there would have been nothing to do in terms of Outlook but '2016 should have been uninstalled before installing '2021. Outlook profiles do not get removed when Office is uninstalled.
The convertor you mentioned has long since gone by the wayside - circa '2015 / 2016 when all Outlook.com accounts were migrated to the new Exchange servers. For most people, manually configuring an Outlook.com account is not recommended since there are no benefits. You cannot manually configure any Exchange based account (the default account type for Outlook.com)
Just in the interests of time, if this is a new install, one quick test you can do to eliminate the possibility of a corrupt Outlook profile is creating a new Outlook profile using the Control Panel Mail app and configure the account to see if the same issue remains (this assumes you can log into this account normally using your browser)
a) - With Outlook closed open the Control Panel <Mail> app
Just in case you need info regarding how to access the Control Panel Mail app, that's described in the following article by Outlook MVP Diane Poremsky
Where is the Control Panel Mail icon?
https://www.slipstick.com/how-to-outlook/where-...
If using Windows 11
How to Open Control Panel in Windows 11
https://www.lifewire.com/open-control-panel-in-...
b) - Select <Show Profile> --> <Add> --> give the new profile a name (no need to remove the existing Outlook profile)
c) - Configure your email account(s)
d) - Set the newly created Outlook profile as the default for the next time Outlook is opened otherwise it'll use the old profile
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