icalendar "verify account information" won't go away and now my calendars are not syncing

**UPDATE** I went into settings >iCloud and a message popped up for me to agree to "terms of service". Guess what? Now everything is syncing again!

Hello. Can someone please help me? icalendar has a "verify account information" message and it will not do anything when I tap/click on it. The "verify account information" message won't go away (it started today) and now my calendars are not syncing! I am a small business owner and having my desktop /iPhone calendars synced is imperative!

I signed into my Apple ID and everything looks good. My credit card payment doesn't expire until next year. I have NO IDEA whey this started all of a sudden ! However, my iPhone 12 Pro Max just automatically upgraded to to the latest software (iOS17.2.1) two days ago 1/21/24.

Can someone please help me? Thank you!