Google OAuth2 Service Account Access Token Request gives 'Invalid Request' Response

Question

I\'m trying to communicate with my app\'s enabled BigQuery API via the server to server method.

I\'ve ticked all the boxes on this Google guide for constructing my J

Answer 1

Be sure to use DateTime.UtcNow instead of DateTime.Now in the GetExpiryAndIssueDate method.

Answer 2

Looks like my guess in the comment above was correct. I got your code working by changing:

"urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Ajwt-bearer"

to:

"urn:ietf:params:oauth:grant-type:jwt-bearer"

Looks like you were accidentally double-encoding it.

I now get a response which looks something like:

{
  "access_token" : "1/_5pUwJZs9a545HSeXXXXXuNGITp1XtHhZXXxxyyaacqkbc",
  "token_type" : "Bearer",
  "expires_in" : 3600
}

Edited Note: please make sure to have the correct date/time/timezone/dst configuration on your server. Having the clock off by even a few seconds will result in an invalid_grant error. http://www.time.gov will give the official time from the US govt, including in UTC.