So, you're looking to try the latest Android Q builds on your Pixel phone? Well, your options are a bit limited at the moment—Google's Android Q system image and OTA file downloads are all broken. That leaves you with the OTA program only.
You should be able to download full system images of Android Q Beta 4 via the Android Developers site. However, all the links just produce 404 errors currently. Our tipster says the links have been down all day. The normal Android Pie system images are unaffected by this outage. So, you can still flash the latest stable software to your phone.
If you want to get on the latest Android Q Beta right now and have not installed a previous version, you can still sign up for the beta OTAs. Those will appear on your phone as an update without visiting the busted developer site. Although, I'd expect the downloads to be fixed before too long.
The problem lies with the redirect from the terms and conditions popup. The link you get after accepting begins with: "https://developer.android.com/dynamic_shared/https://dl.google.com..."
If you remove the "https://developer.android.com/dynamic_shared/" section, you should have a working download link.
Google appears to have fixed the redirect. For a short time, the page had a new download center that combined factory images and OTA files. Google seems to have reverted that and just fixed the links for now. We'll keep an eye out for more significant changes in the near future.
- Android Developers