In our post about Google pulling the Android 8.1 developer preview OTAs, many of you mentioned that you were also having trouble downloading the OTA from the Android Beta Program. Since the OTA downloads for sideloading had been pulled, that was the only way to move to 8.1 without an unlocked bootloader. Well, those problems should now be resolved.
In a post on the Google product forum related to the issue, earlier today a representative from Google let everyone experiencing the problem know that a new OTA should be rolling out now.
This issue has been resolved. For those of you that faced the issue and were reverted back to 8.0, you will be offered a new OTA (which is rolling out now).
The new build number should be identical to the older one, and according to reports on the forum following his post, you may be able to download it now. So if your device wasn't able to install the Android Beta Program 8.1 OTA and you weren't willing to unlock your bootloader to fix it, you should be able to see a new update on your device. If the new OTA isn't showing for you just yet, it should be soon.