Fix "work or school account problem" error

1. Open Settings > System > Shared Experiences by clicking on the notification panel or press Windows  + I > System > Shared Experiences
2. Under Accounts there may be a Fix Now button. Click this and follow the prompts to resolve basic issues
3. If you are asked which account to use, select the one ending @ox.ac.uk (not your email address)
4. You may be prompted to select your account multiple times, even 6 or 7 times is not unusual - keep selecting the same account

If you had an account prior to the introduction of multi-factor authentication in late 2020 / early 2021 then a change in your account details can cause this issue to stick around. The following steps may help:

1. Follow the Fix Now Button solution above first to ensure that all apps have switched over to your new account details
2. Press Windows  + I > Accounts > Access work or school
3. If you have two or more accounts listed, including one based on your email address and one ending @ox.ac.uk, then select the one based on your email address, click Disconnect and follow any prompts
4. After a short while the old connection to your Office 365 account will be removed, leaving the new one in place