This problem surfaced last month and then magically just disappeared. Your SSL config option mentioned system wide changes were being implemented in early September and that’s the timing of when my site started failing. It was down completely for Sept 11 and 12 and without me making any changes it just started working and continued to work fine for 18 days straight and now today it’s failing again.
May I ask what SSL option have you got selected under the SSL/TLS tab at Cloudflare dashboard for your domain ( Flexible, Full, Full Strict … )?
From the article about 525 error which you’re unfortunately experiencing, reading the troubleshooting steps which I am afraid you haven’t went through, I’d suggest to temporary Pause Cloudflare and double-check if you can access your Website over a HTTPS. In other words, your SSL certificate at the origin host/server might need to be renewed. After success, un-pause and make sure your SSL settings are at Full (Strict).
Steps to follow for troubleshooting the 525 error you’re experiencing:
Use the “Pause Cloudflare on Site” option from the Overview tab for your domain at dash.cloudflare.com .
The link is in the lower right corner of that page.
Give it five minutes to take effect, then make sure site is working as expected with HTTPS without any error
Check with your hosting provider / cPanel AutoSSL / Let’s Encrypt / ACME / Certbot and manually click to renew it
Only then, when your website responds over HTTPS, you should un-pause Cloudflare and double-check your SSL/TLS setting to make sure it’s Full (Strict).
I’ve been running it with Cloudflare paused for at least 30 minutes, no failures at all. The certificate expiry date in the browser matches that on the server, the expiry date is 11-Dec-2024.
We are having the same issue on 260+ domains in cloudflare… the 521 error. This is the same issue CF blamed on DNS resolving a week or so ago. It’s back!! Everyone of our clients are screaming mad and CF is ignoring this issue.
Fritex - when I access the site it’s still 525 appearing intermittently. The web server is definitely not down. I’m disabling cloudflare for a longer period of time to prove to you when clouldflare is enabled, the problem comes back. About 1 in every 4 attempts to access the site return a 525 error.
Fritex, once I disabled cloudflare, the site works perfectly repeatedly without failure. With cloudflare enabled it’s very easy to reproduce the failure, fails every 1 in 3 or 4 attempts to access the site, with cloudflare disabled (after waiting 10 minutes) the site performs flawlessly across many dozens of attempts.
