@Freya.G - I have not experienced this before.
If your colleague has any browser extensions installed, they should try disabling them or try a private/incognito browser window.
If you are more familiar with Miro than your colleague, I would suggest the two of you connect on a Zoom/Teams/video call and your colleague shares their screen, so you can see exactly what they are doing - this may be an education/user-related issue and not a technical/Miro issue.
@Robert Johnson Hi, thanks for trying to help.
I did connect with the colleague and he does nothing different than I do. We also tried to use a different browser. Is there no Miro customer support at all who could just quickly connect with him and check?
@Freya.G - If he has a Miro account, he can reach out to the support team via this form.
He could also try a Miro desktop app instead.