More a FYI for @brospars and @lfarhi I changed some settings to remove some restrictions on the first day some joins:
I set it to a higher value 10 posts and 30 replies (this was 3 posts and 10 replies IIRC). Of course feel free to set it to a more reasonable value.
This problem was mentioned in Question: It is possible to edit the course as code? and someone else reported it to me recently.