Once every month my server returns a 502 on all requests

Once every month me server returns a 502 on all request made via Cloudflare. (Ubuntu + Nginx + Lt's encrypt).

Meanwhile, it works perfectly if I make the request directly via the IP address (for example https//:

So I assume it's a problem between the Cloudflare and Nginx connection. The current solution is rebooting the server and then everything starts working again.

I've done a lot of research but couldn't find the cause of the problem. What am I missing?


I agree it is a problem between Cloudflare and your origin server. I'm not sure why you think Let's Encrypt is involved though. Can you explain more about that?

Have you seen this topic on the Cloudflare site?

You say connecting using the IP works. But, you should get a cert name mis-match error from a browser because your LE cert won't contain the IP address used in the URL. And, I can't connect to that IP right now. Is that your real IP?

I moved your topic to the Help section. I'm not sure this is a Let's Encrypt issue but you would have been shown the below form if submitting to the Help section. Please answer them as best you can if you think it's LE related


Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. crt.sh | example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.

My domain is:

I ran this command:

It produced this output:

My web server is (include version):

The operating system my web server runs on is (include version):

My hosting provider, if applicable, is:

I can login to a root shell on my machine (yes or no, or I don't know):

I'm using a control panel to manage my site (no, or provide the name and version of the control panel):

The version of my client is (e.g. output of certbot --version or certbot-auto --version if you're using Certbot):


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