Students cannot login - need admin approval - but admin approval has been given

We have set up SketchUp for Schools using our Microsoft tenant. As an admin, I can successfully log in. However, students cannot log in and are given a message that it needs “admin approval”. When I look at the Azure back end, admin approval has indeed been given for the entire organisation.

I haven’t been able to find any MS-specific instructions for setting up, but as I can log in, that bit seems fine. It’s purely this admin approval, which has been given on every reference to Sketchup I can find in Azure, and matches with all MS documentation I can find on giving approval for apps.