An API (FastAPI & Azure function) endpoint with content type of application/x-www-form-urlencoded not working when deployed in app service plan

Question

I have an azure function that usages fast api. When api is deployed in serverless plan, all endpoint works perfectly. However, when it's deployed in app service plan a login endpoint, when requested from front-end shows 422 (entity not processed) but works when requested from api doc"domain/doc". The endpoint accepts a content type of application/x-www-form-urlencoded. All of the other endpoint also work when requested from the front-end.

This is the source code for the front-end application

const formData = new URLSearchParams();
  formData.append("username", username);
  formData.append("password", password);
  console.log(formData.toString())
  const response = await fetchClient.post<Token>(
    "/v1/login",
    formData.toString(),
    {
      headers: {
        "Content-Type": "application/x-www-form-urlencoded",
      },
    }
  );

• I have confirmed that both application have exactly same configuration

The issue has been resolve by using / at the end of the each request

Answer 1

• I have resolved this issue by using / at the end of the each request. I am not certain about the cause.