Since it looks like this beta has been released in the normal release channel.
So any problems with the regular release version 20.2.2401 (build 20.2.5130.561) UI-1.0.502 should be in the main Avast Free Antivirus / Premium Security forum.
Sorry I wrote the previous feedback so quickly.
After I installed avast beta, avast interface was like a website til I restarted the laptop. That was accessible.
After I restarted my computer, the avast wasn’t accessible again.
This is no longer a beta release, see https://forum.avast.com/index.php?topic=233119.0
If your version and build number doesn’t match Avast version 20.2.2401 (build 20.2.5130.561) then you need to do a program update and reboot.
If it doesn’t then start your own new topic and give more details of the problem you are experiencing.