I have noticed that starting approx. mid of December, I cannot access my activities page from a mobile device (iPhone 5s, iOS v. 10.2). When pressing "Logon" link on a welcome page (credentials are already stored as page data), I see that it tries to authenticate but returns with HTTP 400 bad request (see screenshot)
Interestingly, after page refresh in a browser I am being authenticated (can see my profile page etc) but Activities remain empty.
Already tried to clean up browser data / cache and re-login but this did not help.
Desktop version (Mac, Safari) works as expected. Any hints?