I am going to assume you've fixed it by now - but for anyone else having the same issue (I just had it today, Oct. 24) take these steps to correct it. When I would click LOGIN TO GTW - it would look like it was processing, then return to the same error (API/403) under details. Combining things above - I simply: 1. Opened an incognito window 2. Logged into Marketo 3. Logged into GTW from Launchpoint Closed the window and the error was gone - I returned to the non-incognito window, hit refresh and it was resolved there as well. I suspect this was due to someone changing the password on the account.
... View more