Calibration is not responding

Hello,

Anybody experiencing this issue of the Apple TV 4K on tvOS 14.5 and iPhone 12 Pro on iOS 14.5 not being able to communicate with each other during calibration? iPhone 12 Pro is stuck on PREPARING (both on video and audio calibration on the TV).

Used the same iPhone 12 Pro to calibrate the Apple TV HD and it worked without any issue.

Any tips on how to fix?

BTW, hard rebooted both iPhone 12 Pro and Apple TV 4K (not the new one). Ensured both are on the same network, too. Still not working. Stuck on Preparing.

Thanks.