Using New Outlook on Windows for professional communication and productivity
Dear johnboydavies,
Welcome to Microsoft community.
You seem to be experiencing outlook keep popping up with error prompts, I understand how frustrated it is. Usually, this problem is related to the outlook app, and you can fix it using the following methods.
#Method1, Repair the outlook app, if you are using the new outlook app, please find its icon on your computer, right-click on it and go to App settings>APPs>Reset>Repair/Reset, in this way you can repair or reset it.
#Method2, Re-add the account. Delete the new outlook app's original account, and then re-add your account back to it, this process can rebuild your outlook profile and reset the link from client to the server.
#Method3, to access webmail, use your browser to access outlook.com, the purpose of this is to test if the problem is with the account itself, usually you won't get this error with webmail.
I hope these methods solve your problem, and let me know if you have any more questions!
Best regards,
Harris-MSFT |Microsoft Community support specialist