Calendar Hiccup

[RideForever]

Operating an iMac, running macOS High Sierra, v10.13.3
Ever since returning after a 3month absence and after creating a new event in Calendar, any time I want to add an Invitee, there is a popup "Calendar will be unable to send the invitation. To be able to send invitations, you need to create an address card for yourself in Contacts."
I actually have (had) an address card and even added one just in case but the popup persists and no invitations sent.
Suggestions would be welcome.

 

[chas_m]

Operating an iMac, running macOS High Sierra, v10.13.3
Ever since returning after a 3month absence and after creating a new event in Calendar, any time I want to add an Invitee, there is a popup "Calendar will be unable to send the invitation. To be able to send invitations, you need to create an address card for yourself in Contacts."
I actually have (had) an address card and even added one just in case but the popup persists and no invitations sent.
Suggestions would be welcome.

You have probably not designated the card as “Me” (ie the administrator), like so:

 

[RideForever]

Thank you