SOLVED iatgen Qualtrics error

Via Carpenter et al.'s code https://github.com/iatgen/iatgen, I was making my own IAT -a reaction time test- in Qualtrics. It worked perfectly, until this week when I wanted to upload my final version. 
Somehow I now see the following block after uploading the .qsf in Qualtrics:
I have tried several computers that all have a keyboard, but this question block does not go away.
When trying to ignore this and previewing the test, the following pop up shows:
Clicking OK or using another webbrowser does not help.
And even previous versions of the test that were already tested by other people now give the same problems.
Does anyone have an idea what might cause this and how to tackle it?
I feel like it can't really be the code, as nothing has changed in the code, but how Qualtrics reacts to it has changed.
Your help would be much appreciated!

Best,
Tine