The problem began after an UpdraftPlus backup stalled while processing a large backup.
Troubleshooting already completed:
UpdraftPlus is no longer active/present in the plugins folder
Really Simple Security was temporarily disabled
W3 Total Cache was temporarily disabled
.htaccess was temporarily renamed
The 503 remained after each test
The public homepage still works
cPanel and File Manager still work
Disk space, inode usage, bandwidth, and daily-hit limits are not exhausted
I have restored the renamed files and plugins to their original names.
Please confirm whether /wp-login.php is being blocked or rate-limited by InfinityFree’s server-side protection, or whether the account is under a temporary CPU/resource restriction.
Please do not suspend, deactivate, or delete the account. I am preparing to migrate this website to an existing premium iFastNet hosting account.
I can confirm that the page is not being blocked or has any limits placed on it other than the overall account limits.
This is a community forum so that is out of our control. Suspensions for hit limits and CPU limits are handled by an automated system and not something that can be turned off
I tried opening the login page, and I see the same issue.
When I open it with my browser’s developer tools open on the Network tab, I see that the login page is responding with a redirect, pointing it back to the same URL. This happens four times, and then the page responds with the 503 error, which is probably some kind of rate limit or loop detection blocking further requests.
So the 503 error is not the issue, it’s a symptom of the redirect loop. As to why your website is redirecting, I’m not quite sure. The headers say that the redirect is done by WordPress (so it’s not a server issue or a .htaccess issue), but I cannot think of a reason why this would happen.