Getting 'you cannot reject the app version in the current state' error trying to reject binary waiting for review

You need to go to the TestFlight, expire the build and then go back and try to remove from review. It works for me.

I tried again after a few hours and it worked and I didn't get the error.

Try to reject the binary in App Store Connect iOS app

Couldn't reject it on App Store Connect site, but I rejected it in the app without problems - only 4 minutes after app status changed to "Waiting for Review"