The Zynga poker app no longer rotates.
I checked - the orientation is not locked.
iPhone 6s, iOS 14
Question marked as
Update your iPhone to current and try again. iOS 15.6 is current.
Update your iPhone, iPad, or iPod touch - Apple Support
Delete the app and re-load it and try again.
Then check with vendor app support.
Contact a third-party vendor - Apple Support