This instance has already started one or more requests. properties can only be modified before sending the first request.

The error message “this instance has already started one or more requests. properties can only be modified before sending the first request.” indicates that you are trying to modify a property of an object after sending a request. In some cases, the API or library you are using allows property modifications only before making any requests.

Here’s an example to illustrate this issue:

    
      // Creating a request object
      const request = new XMLHttpRequest();

      // Setting a property after sending a request
      request.open('GET', 'https://api.example.com/data');
      request.send();
      request.timeout = 5000; // Trying to modify the 'timeout' property

      // The above modification will throw an error
      // "this instance has already started one or more requests. properties can only be modified before sending the first request."
    
  

In the provided example, the ‘timeout’ property of the XMLHttpRequest object is modified after sending the request. However, this modification is not allowed since the request has already been initiated.

To fix this issue, you need to ensure that all required property modifications are done before invoking the send() method or making any requests.