Issue with 404 error, ECONNABORTED, ECONNRESET

Hello,
For about 1-2 months we have started to have strange behavior using Cloudflare and unfortunately, we were forced to deactivate it on our client’s dashboard. We are looking for your support and guidance to fix them. Many thanks in advance.

  1. All of our websites are on Cpanel with SSL active from Let’s Encrypt and set to force HTTPS; also on CF SSL is set to Full or Full Strict.
  2. We are using an uptime monitor called monspark.com (we have also added their ips to the allowlist in CF) and if CF is active it responds with a 404 error, also if we go to CF apps and try to preview GTM is not loading properly; ofc if CF is deactivated or not using the proxy to A or www everything is back 2 normal. We also receive 404 errors even from Google Ads that suggest the destination pages are not available.
  3. To consider that our hosting provider shorturl . at/iBR37 is using Bitninja as a firewall and we thought that may be incompatible with Cloudflare.
  4. Another issue represents with the payment processor, if CF is active the response for payment is not being delivered to the website. (ofc is working with CF off)
  5. About 2 days ago the following websites were giving direct 404 errors (similar to typing an existing link) and nothing was working like accessing the backend and also we site . com/cpanel. After CF was deactivated everything was back to normal. shorturl . at/yEIL9, shorturl . at/hxBS8, shorturl . at/cdhF3, shorturl . at/ceMT6, shorturl . at/cdpt1, shorturl . at/jLSTX, shorturl . at/iBCG0

Hope I provided enough information for debugging if more info is needed please let me know. We really want to fix this issue.

All the best and thanks again.

Sorry got some error with links here there are

https://shorturl.at/yEIL9, https://shorturl.at/hxBS8, https://shorturl.at/cdhF3, https://shorturl.at/ceMT6, https://shorturl.at/cdpt1, https://shorturl.at/jLSTX, https://shorturl.at/iBCG0