Microsoft login keeps popping up

Hello,
We have a student which uses the SketchUp website.(microsoft account)
On every device he works, he can login to sketchup but after every action sketchup(the browser) keeps popping up to sign in again to Microsoft. When logging in again it’s accepted but it keeps repeating.

We tested this on different devices. Other students have no issues.
What can cause this?
Thanks!
Roel