Getting 526 on Cloudflare Tunnel Randomly


Intermittent 526 Errors in Cloudflare Tunnel - Urgent Resolution Required

Ticket Details:


We’ve been experiencing intermittent 526 errors with our Cloudflare tunnel setup. These errors occur sporadically and then resolve on their own, affecting the performance and reliability of our services.

System Details:

  • Domain Name:

Steps to Reproduce:

  1. Set up a Cloudflare Tunnel following standard configuration.
  2. Route traffic to the origin server.
  3. After some time, 526 errors start appearing.

Configuration Details:

  • No SSL certificate installed on the origin server.
  • Using Cloudflare’s own SSL certificate.
  • SSL settings on Cloudflare set to Full

Error Logs:

CF Ray ID: 7fed97fdbb87985e-SJC


  1. What could be the root cause of these intermittent 526 errors?
  2. How can we resolve this issue to ensure uninterrupted service?
  3. Are there any recommended best practices for SSL/TLS settings to avoid such issues?

Additional Information:

We’ve ruled out server downtime and network issues on our end. Also, we’d like to mention that we are looking for a resolution that doesn’t involve setting SSL to ‘Flexible’ on Cloudflare.

We look forward to your prompt response as this is affecting our operational efficiency.

Best regards,
Naaman Saif
Software Engineer

Also I would like to mention that this only occurs for our users in US California. For our team in Pakistan this has never occurred. If that helps.