A few users are receiving timeouts when attempting to load the website

My site is working perfectly for me, every online test I run works perfectly, but 3 users have contacted me to tell me that loading the URL results in a timeout on their end, no Cloudflare page and no errors shown in my Cloudflare account. What would be the recommended steps to debug? All 3 of these users are located in the same region of Canada.

To confirm, are they seeing a browser error? If it is still happening, have them try https://www.example.com/cdn-cgi/trace (where https://www.example.com/ matches your site, of course), this will confirm if they’re able to reach Cloudflare at all.

Assuming that this is still ongoing, of course – It could easily be transient issues with their ISP, or their ISP’s route to Cloudflare, in which case it will likely be resolved.

I got some more info from some of the users. If they go to the cdn-cgi/trace link, they see a similar page to me. But navigating directly to the website, they get a Error 522. See attached. Interestingly, it’s only these few users consistently getting this error, the site appears to work fine for >95% of users.

All we know is that something on the backend causes a timeout while Cloudflare attempts to establish a connection with your backend.

My advice is to reach out to your host and explain that you set up Cloudflare recently; they likely have a firewall in place that blocks bursts of connections coming from the same IP.
In typical scenarios, you wouldn’t trigger this. However, while using Cloudflare, many of the connections may seem to come from the same IP.

The root of the error could be somewhere else. However, from my experience, this is typically a good place to start digging in.

I have confirmed that there is no firewall in place on the host side.

Interestingly, all the users reporting issues appear to be on the same ISP (Bell MTS).

One of them has confirmed that either using a VPN or switching to cellular data allows them to load the page fine.

It could be that the particular Cloudflare POP that you are hitting is having issues… But from experience, it is more often on the host side (I say that having previously run a small host).

Could this be related? See: https://viewdns.info/propagation/?domain=gocwinnipeg.com

I have discovered that when these users attempt to load the page, the server is sending the SYN+ACK to the SYN received from Cloudflare, but never receives the ACK back from Cloudflare and instead retransmits the SYN+ACK several times.

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