Add account Outlook

When I add an Outlook account, I get the following message:
unauthorized_client: the client does not exist. If you are the developer of the application, configure a new application through the application administration site at

Had the same issue this morning with a clients system, removing and re-adding the account fixed the issue

I’ve already tried it, but it’s still not working

Same here. Used to work fine, now on one of my machines keeps giving the error message above. Still working on laptop.

If the account is set to IMAP and the version you are running is older than v7.2.34959 then take a look at this Reaction to the authentication problem note, which is in fact prominently displayed on the main forum page. Short answer: update to the latest v7.2.35128 build.