How do I fix error "Cannot Verify Server Identity" on my iPhone

You probably got tricked into installing a rogue calendar; your phone does not have a virus. In the future beware of "free" offers

See this Apple support link→Delete spam calendars and events on iPhone - Apple Support

or watch this companion video:

Delete Calendar Spam

Did you figure this out yet?! I get the same pop up several times in a row and even went to the AT&T store for help. Not a help! I don’t have a calendar app other than the one that comes with my phone and have had it for years. I have tried deleting newer apps but nothing has worked.

It is not a different calendar app, it is the regular calendar app and a spam calendar has been added. Check the link from Lawrence Finch and follow the steps in the video to check your calendars and remove the spam one.

Try going to settings>apps>calendars

Delete any unrecognized accounts there. I had the same issue and this worked for me!

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