What “Failed to fetch” Means

That error does not come from your API code directly.
It usualy means browser stopped the request before it could give jQuery response.

Common causes:

1. CORS issue → API not allowing requets from your domain.

2. Network/URL issue → wrong URL, DNS issue, HTTPS mismatch (calling HTTP from HTTPS).

3. Response format issue → API returned invalid or unexpected content (like plain content('0')) instead of JSON/XML/text that your jQuery expects.

Why might you still see TypeError: Failed to fetch?

1. Not really hitting your handler

   • If your page is /ControllName/ForgotPassword, then the URL should be:

     /ControllName/ForgotPassword?handler=ForgotPwd&UserName=xxx
     
     

     not just /?handler=....

2. CORS or HTTPS mismatch

   • If you’re calling this from another domain (or from HTTPS → HTTP), the browser blocks it.

   • In that case, “Failed to fetch” shows before it even gets the response.

   • You can check program.cs file both configuration.

3. Exception on server

   • If the server throws inside OnGetForgotPwdAsync, the API may return 500 Internal Server Error.

   • Check Network tab in DevTools (F12) → what’s the actual status code?

Fix Suggestions

1. Correct the URL

If your page is a Razor Page at /ForgotPwd, then:

const resp = await fetch(`/ForgotPwd?handler=ForgotPwd&UserName=${usrname}`);

2. Make sure to return text properly

If you always want text back:

return Content("0", "text/plain");

3. Debug in DevTools

• Open Network tab → click the request → check:

  • Status code (200? 404? 500?)

  • Response body (is it really 0?)

Most likely issue = wrong URL (/?handler=...) or server error.