Creating new speaker profile and submission does not work

I already have an existing account and have done submissions before. When I now login for a conference I have not yet created a speaker profile, and consequently not submitted a talk, nothing happens. At the step where I am usually told to create a speaker profile there is just an empty page (In browsers where I already tried to login). When I try to login in a different browser, it seems like the login goes through, but it is still the same page as before, just the part on the right, where the login mask is greyed out. (I attached a picture.)

I tried it out with Devoxx UK and Devoxx Poland and have the same issue with both. A friend, who already created a speaker profile and created submissions for Devoxx UK, does not have the issue with the Devoxx UK page, but he also has the issue with the Devoxx Poland page. Therefore we assume that most likely the issue is for people that already have an existing account in general but have not created a speaker profile for that specific conference. (Also I am able to look at my proposals for Voxxed Days Ticino and Voxxed Days Amsterdam, which also supports my theory)