Error message when opening a dashboard for the second time

Dear all,

Through app.powerbi.com I am sharing several dashboards with my colleagues.

On Monday one of these dashboards could not be opened by one of the recipients anymore.

I re-sent the release message and the colleague could open the dashboard. When returning later this day and trying to open the same dashboard for a second time, the colleague received following message...

I did not do anything else than in the past and it worked. What do I or the recipient need to do?

Hopefully some of you can help me...

Best regards

Torsten