Amazon prime not working in 1080p, not even working on 720p

in ZenFone 6
After recent update, Full HD content stopped working for Asus 6z.
Make it working again.
After recent update, Full HD content stopped working for Asus 6z.
Make it working again.
Comments
Amazon prime and other OTT services. All are working in standard definition.
Seems to be playing in HD for me.
Hi, request you to provide us with your device's latest firmware version. You can follow the below instructions to do the same: Settings -- About -- Software Information
Check streaming quality in setting. See if it's on best or not.
It should show 2.35 GB/hr for best if you can stream in full HD. If it's less probably restart or reset your phone
For me i get full HD option
Maybe it could be due to Widevine change just download DRM info from play store and check for security level it should be L1