Error message "Connecting to Internet Calendar Failed"

I made an error in entering an Internet Calendar address. Now I get this error message every time that I open eM Client even though the address entry box is blank. How do I get rid of the error message?

Hello Mike,

Could you please try deleting the Internet Calendar in the Calendar section (it will be in the Internet Calendars folder) and try adding it again?

Thank you,

It worked - thank you.