Calender with holidays and yellow triangle

Hi all,
for a few days now I have this triangle next to my holiday calender (which is an imported calender). I’ve tried to repair the calender but this was not possible as button was inactive.

Does anybody here have an idea?

Bildschirmfoto 2023-06-29 um 16.23.33
Bildschirmfoto 2023-06-29 um 16.24.03
Bildschirmfoto 2023-06-29 um 16.24.14

Right-click on the calendar folder and choose Delete.

Then add it back again by right-click in the folders area and choose Import Holidays > Germany

:joy:
Sometimes solutions are so simple that they are not considered to be the right ones.

Thx :+1: