`fetch(...Resend...)` is not working. No error caught nor `console.log()`

For Workers & Pages, what is the name of the domain?

.pages.dev

What is the error number?

none

What is the error message?

none

What is the issue or error you’re encountering

fetch(...Resend...) is not working. No error caught nor console.log()

What are the steps to reproduce the issue?

After hundreds of tries I’m starting to think that fetch() doesn’t work on pages.
The code is pretty simple as shown below.
It works fine in my local environment got no problems.
But in pages it just doesn’t work.
catch doesn’t catch any errors, and nothing seems to work after fetch().
It just seems that fetch() destroies the app without any error.

my code :
try { ... const res = await fetch('https://api.resend.com/emails', { method: 'POST', headers: { 'Content-Type': 'application/json', Authorization: Bearer ${env.RESEND_API_KEY} }, body: JSON.stringify(body), }) ... }

Or is there any alter way to send mail in pages?

Screenshot of the error

Of course I tried with or without 'Cache-Control': 'no-cache'. and not working without response or error