Getting error code 525 when trying to use subdomain in worker

We are testing our worker code by accessing a subdomain that reflects the main site instead of the main site, so instead of

Everything has worked well for about 4 weeks until yesterday when calls to the subdomain started to return “error code: 525” instead of the page data.

What has gone wrong? How do I fix it?


Is there a chance that the SSL certificate for the site the worker is calling has expired?

I can a check and got
Status Code: 200 hostname port 443 path /
error code: 525
The path is a worker route that I use to text my worker code. I didn’t find anything in the cloudflare system that calls a ssl cert. Just created under “Worker Routes”

The universal certs are active and expire in 3 months.

Review Universal Certificate for, *

The certificates in the pack listed below are managed and auto-renewed by Cloudflare.
Certificate Validity Period 3 months
2024-05-27(Managed by Cloudflare)

Thanks for your help :slight_smile: