Outlook not accepting Exchange credentials

I am trying to add an exchange profile to Microsoft Office 2016 (windows 10). It picks up the email address, however, when it is authenticating it asks for the credentials, but does not accept them and pops straight back up.

So far i have tried; both repairs for office, autodiscover reg keys, checking autodiscover on dns host, Adding a Disable WAM keys, uninstalling office, removing from domain, windows updates.

I have managed to add the profile to Windows 10 Mail and it works.
jon_eccomputersAsked:
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Jeremy WeisingerSenior Network Consultant / EngineerCommented:
Download and run the Microsoft Connectivity Analyzer Tool and see if it points out any issues:
https://docs.microsoft.com/en-us/previous-versions/office/exchange-remote-connectivity/jj851141(v=exchg.80)
Asif BacchusI.T. ConsultantCommented:
Some housekeeping:  Have you checked the user's credential manager via control panel?  Perhaps they have some errant old credentials causing a problem.  Also, have you ensured you specify the domain when entering the username?  You may want to try both down-level (domain\username) and UPN (user@domain.tld).  And yes, if those fail, then Jeremy's suggestion of the connectivity analyzer is a great idea!
Hani M .S. Al-habshiContributor as IT ExpertCommented:
Edit the authentication settings for the virtual directories or Client Transport  in the Exchange Admin center enabled Windows Authentication -NTLM, Negotiate and Basic.
SysToolsData Expert - Recovery,Backup,MigrationCommented:
Check out the blog, as this problem occurs due to various scenarios:
https://www.systoolsgroup.com/updates/outlook-prompting-password-connected-ms-exchange/
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Windows 10

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