CognitiveServices Language TextAnalytics API is not working

I have used this package Microsoft.Azure.CognitiveServices.Language.TextAnalytics version 3.0.0 in one of my legacy application.

var client = new TextAnalyticsClient(new ApiKeyServiceClientCredentials(cognitiveConfiguration))
 {
     Endpoint = cognitiveConfiguration.Endpoint
 };

 var kpResults = await client.KeyPhrasesAsync(
                true,
                new MultiLanguageBatchInput(
                    new List<MultiLanguageInput>
                    {
         new MultiLanguageInput(language, "1", query)
                    }));

• client.KeyPhrasesAsync method is throwing below exception suddenly.

Error response:

"StatusCode": 3,

"ActivityId": "4000000a-0001-fd00-b63f-84710c7967bb",

"Errors": 

        "Code": -2146233088,

        "Message": "Operation returned an invalid status code 'Gone'",

        "FullMessage": "Exception: Microsoft.Azure.CognitiveServices.Language.TextAnalytics.Models.ErrorResponseException\r\n

After troubleshooting i've found that client.KeyPhrasesAsync uses this request url https://{{region}}.api.cognitive.microsoft.com//text/analytics/v2.1/keyPhrases?showStats=true and most of the articles were saying v2.1 has been retired on February 2024 but am not getting, how this was working till Oct 7th 2025.

Is anyone facing similar issue ? Can someone please provide suggestion on fixing this issue.