Error: 16 UNAUTHENTICATED: Failed to retrieve auth metadata with error: invalid_grant

I am using google ads api for reporting and keyword plan purposes in our application. it was working perfectly fine some time ago But now i'm facing this error Error: 16 UNAUTHENTICATED: Failed to retrieve auth metadata with error: invalid_grant at Object.callErrorFromStatus (C:\Users\ssc\

Error: 16 UNAUTHENTICATED: Failed to retrieve auth metadata with error: invalid_grant

I am using npm's google-ads-api for reporting and keyword plan purposes in our application. it was working perfectly fine some time ago But now i'm facing this error Error: 16 UNAUTHENTICATED: Failed to retrieve auth metadata with error: invalid_grant at Object.callErrorFromStatus (C:\User