I posted this solution on a similar (but not exactly the same) topic in Cloudflare Community. I’m posting it here as well in case it helps anyone in the future as something to think about:
Every possible page on the site was redirecting automatically to the home page without any such rules being set on our end at the host or in Cloudflare.
Every possible visit was also triggering a captcha.
No changes to Cloudflare nor Siteground settings were made.
It came out of the blue.
Disabling cloudflare completely resolved both issues (no more captchas and no more redirects) but it was not resolving the underlying trigger, just a bandaid temporary solution and nothing else.
Enabling cloudflare and disabling bot attack mode and placing security under “essentially off” didn’t do anything either.
Disabling Cloudflare’s page rule → cache everything, stopped the redirects but didn’t stop the incessant captchas.
After troubleshooting with Siteground and Cloudflare for 8-10 hours, we finally realized what happened.
We use a VPN to test our site across the world.
Siteground’s firewall had automtically and unknowingly blocked a key IP related to the VPN, which ended up blocking all other IPs from that same VPN. I can’t explain how/why but that’s the story.
Once Siteground customer service unblocked this single IP, all captchas and all of the automatic redirects suddenly ceased across all IPs.
Everything was back in working order as if nothing happened.
We renabled all of Cloudflare’s original security settings (bot attack mode, stronger security level) and page rule (cache everything) and everything works just fine now.
Back to normal.
I can’t explain how/why everything interacted the way it did between Siteground and Cloudflare to cause these issues, but it obviously did somehow.
This food for thought might also help you narrow down why you’re experiencing this issue: Strange Redirect Issue - #7 by frkllc