Unable to translate due to the Unauthorized error

I am using the ‘AzureAITranslator’ API for text translation. After a few days of usage, I am getting this error:

StatusCode: 401, ReasonPhrase: 'Unauthorized'

I tried the following steps to get it to work but still getting the 'Unauthorized' error.

1. I initially used Key 1 for text translation. I changed it to Key 2.

2. Regenerated both the keys.  

 Following is the code being used:  

private static string key ="-------";
private static readonly string endpoint = "https://api.cognitive.microsofttranslator.com/";
private static readonly string region = "-------";
public static async Task<string> TranslateString(string from, string to, string translatedText)
       {
           string route = "translate?api-version=3.0&from=" + from + "&to=" + to;
           string xmlString = translatedText;
           string result = "" ;
           try
           {
              object[] body = new object[] { new { Text = xmlString } };
               var requestBody = JsonConvert.SerializeObject(body);
              JsonConvert.SerializeObject(body);
               using (var client = new HttpClient())
               using (var request = new HttpRequestMessage())
               {
                  request.Method = HttpMethod.Post;
                  request.RequestUri = new Uri(endpoint + route);
                  request.Content = new StringContent(requestBody, Encoding.UTF8, "application/json");
                  request.Headers.Add("Ocp-Apim-Subscription-Key", key);
                  request.Headers.Add("Ocp-Apim-Subscription-Region", region);
 
 
                  HttpResponseMessage response = await client.SendAsync(request).ConfigureAwait(false);
 
                   if (response.IsSuccessStatusCode)
                   {
                      Console.WriteLine("Success , translated text:");
                      result = await response.Content.ReadAsStringAsync();
                      Console.WriteLine(result);
                   }
                  else
                   {
                      Console.WriteLine("Error: " + response.StatusCode + " " + response.ReasonPhrase);
                   }
               }
           }
           catch (Exception ex)
           {
              Console.WriteLine("Error:" + ex.Message);
           }
           return result;
       }
 

The

I faced a similar issue last week but was able to get it to work by creating a new translator API.

Could you please let me know what could be the reason for the Unauthorised access error?