anyone that can provide some guidance would be appreciated, tried rebooting, upgrade the firmware, nothing seems to work.
You'll generally see bad gateway if you attempt to access an access portal resource and aren't authenticated.
-For WebUI, please make sure you're appending the port to your URL (8080 by default) like https://10.0.1.1:8080
-Try opening a new tab/browser window, and use Incognito/InPrivate mode to ensure you're not caching anything from an old session.
-If something has gone wrong, rebooting the firewall should restart any processes that the WebUI relies on to work.
If you still can't access WebUI, I'd suggest opening a support case by using the support center link at the top right of this page.
WatchGuard Customer Support