I share my yahoo account in Calendar.

it sends an email to accept my calendar co-owner invitation.

i get the following error message:

Sorry, this invitation isn't valid anymore. The sender may have taken away your permission, or you may have already declined this invitation. If you'd like to see this calendar, ask its owner to share it with you again.

drop the yahoo email info.

go thru the same process.  same error message.

can you help?

thanks!