linking emails with mac calendar
It appears I've lost a basic function. Until recently, I could make an event in Mac Calendar, then drag an email from Mac Mail, and it would create a link from Calendar back to that email.
Today, if I drag an email, it makes a link that goes to a blank page in Safari. The supposed link is nothing but the subject line of the email.
Looking at events I made a few days ago, I still have email links, and they work. But I can't make new ones in new events. What happened?
MacBook Pro 14″, macOS 12.2