Using all of the above has resolved this for us when the usual workaround (just deleting the entries in Keychain) doesn't work.
In Outlook > Tools > Accounts > input the password into the email account(s) you're having trouble with.Plus, get 1 TB of cloud storage, document sharing, ransomware recovery, and more with OneDrive. In Outlook > login to any accounts that you're prompted for Create your best work with the latest versions of Word, Excel, and other Office apps.Open Outlook > input password to unlock login in Keychain.Open Keychain Access > (View > show invisible items) > search for and remove entries related to 'exchange', 'office', 'adal'.It doesn't crop up every day/week/month, isn't related to password or other issues specific to an account, and appears to be a problem with Outlook/Keychain interaction. This is an issue that has been around for several years going back to at least Outlook 2016 for Mac. Our users having trouble are using O365 accounts in combination with Duo (but Duo doesn't seem to be the problem). Break passwords to Microsoft Office documents and files in OpenOffice, Apple.
I wanted to add some notes about our workaround for this because sometimes just deleting those entries in keychain isn't (always) enough. Recover, remove or circumvent passwords protecting documents created with a.
