Not sure if anyone else has had the same problem, however when I choose Activity Diary from the Logbooks menu on the main bar, I get a page telling me to log in, even though I am already logged in.
If I go to My Logbook and choose Diary from the options once on this page, it then takes me to my Diary.
Obviously not much of an issue but thought you might like to know.
Chrome
Windows 10 64 bit
Hope that helps?