Gnome Calendar error

After installing Gnome Calendar i get the attached error when i'm trying to run it. What am i missing?

Form this Picture it looks like You have installed the Snap-Version? To control that open the Terminal and type snap list

Maybe You should better try the apt Version. To install these open the Terminal and type sudo apt install gnome-calendar

I have been uninstalling Gnome Calendar in the meantime. Then i have installed it again in the terminal and i receive the same error message when trying to run Gnome Calendar afterwards.
I have attached a screenshot of the result of snap list. Not sure what to make of it..

I wanted to take a Look if the Gnome Calendar is in this List. But obviously it isn't. I would make the Suggestion to delete Snap from Your System to test if the Error would still appears but if You want use Snap this wouldn't be a good Idea.