Yahoo Calendar events have all disappeared

My iPhone and iPad are set up to use my Yahoo calendar as default. I also have iCloud calendar.

I can view, edit, and add to that Yahoo calendar from the iPhone calendar app on my phone. This has worked fine for 3 years or more.

Suddenly, the Yahoo calendar on my phone is empty of all historical events. I’ve done everything I gleaned from other discussions: made sure I was syncing all calendar events, Yahoo calendar selected, removed and re-added the Yahoo calendar, removed and re-added the Yahoo account. Nothing worked.

I can see my yahoo events going into the future but everything from last year has gone. I have it set to sync “all events”

any ideas of a fix?