Was able to download the beta and reboot, once rebooted, phone showed this notification:
"Installation failed, already downloaded the update file and will try again later."
(not exact wording, but as best as i can recall).
Then app optimization started. I waited until it finished. Phone prompted me to reboot again.
I did but got the "Installation failed" once again. I am on the 4th try now and my phone is hot.