Fetch Workers API occurs 523 error

Hi, I build two workers to serve my site:

  • worker A: a API server that response data
  • worker B: a page render server, use Flareact framework as SSR, will request worker A’s API


  • when worker B request worker A API, always return 523 error – origin is unreachable, I use xxx.worker.dev or my custom domain for worker A API address, same error. And I am sure the worker A runs well, I can use curl or browser to request the API, no bug.

I want to know where the problem may be and how to troubleshoot it, thank you

I have same question :frowning:

I think this is the answer: