Planner Patch ETag Issue

Getting below error for planner task update operation
{"error":{"code":"","message":"The If-Match header contains an invalid value.","innerError":{"date":"2024-10-24T15:32:02","request-id":"b976210d-9970-4997-9e64-bef1c6c8e9d5","client-request-id":"b976210d-9970-4997-9e64-bef1c6c8e9d5"}}}

string currentETag = "W/\"JzEtVGFzayAgQEBAQEBAQEBAQEBAQEBARCc=\""; 
httpClient.DefaultRequestHeaders.Add("If-Match", currentETag);

Need help of right combination for passing the correct etag I tried removing backlash and adding double quotes and other combinations given across articles.