Unknow Error when setting up CodeWhisperer with VS Code.

The following is my AWS Toolkit Logs:

2023-04-30 16:46:50 [ERROR]: API response (oidc.ap-northeast-1.amazonaws.com /token): {
  name: 'InvalidGrantException',
  '$fault': 'client',
  '$metadata': {
    httpStatusCode: 400,
    requestId: 'dbbba2ef-e5f1-4b20-9d92-d7869b57e732',
    extendedRequestId: undefined,
    cfId: undefined
  },
  error: 'invalid_grant',
  error_description: 'Invalid grant provided',
  message: 'UnknownError'
}
2023-04-30 16:46:50 [ERROR]: aws.codeWhisperer.sso: Error: Failed to connect to IAM Identity Center [FailedToConnect]
	 -> InvalidGrantException: UnknownError

After entering my AWS access portal URL, got a pop-up, choose Copy Code and Proceed, I did get a message said AWS Toolkit for VSCode can now access your data.. However, VS Code still failed to connect to IAM Identity Center, and gave me the Error log above. What else I could do to fix the error?

Also, I have done the SSO token provider configuration at ~/.aws/config by casting aws configure sso. How about ~/.aws/credentials? should I leave it empty? currently it's my old IAM user ACCESS KEY ID & SECRET ACCESS KEY.

Thanks!