Mac Mail: Cannot save drafts or reply for one account

Hello, I need help with the Mail app on Mac. When I switch to the @ldance.cz account, 
a message appears saying that the message could not be saved to the Drafts folder. 
If I close it immediately, the message is deleted, but as soon as I write something in the message,
the email cannot be deleted or saved. For this reason, I cannot reply to any enail from this account. 
This error only appears on Mac, I also have the same account on iPhone and everything works there.

I also contacted the domain and email administrator and there is no problem there.