My Canvas app uses a custom connector that has worked fine for all of us (3 people) until today. It turned out that a colleague was using the old version of the app during last month. After refreshing to the latest published version, he got a 401 HTTP error. For the rest of the people, the connector works fine. He has already tried logging out and back in and opening the app in incognito mode, but that didn't help. What could be the problem?