Accessing the Adwords API from a test account

Question

Google

I want to test requests in a test account. Requests require a developer ID. I create a second account (not a test one) and request an identifier there. Having a developer ID from a non-test account, Client ID, Client secret and OAuth2RefreshToken from a test account, I try to get a list of campaigns, but I get an error:
Failed to refresh access token.
{
"error" : "invalid_grant"
}
Has anyone encountered this situation? It’s also confusing that the main account and the test account were not connected in any way, and when requested, I use data from both accounts.

Answer 1

Good afternoon. Have you solved the problem?
I really need a paid consultation on the Google API. I hope very much for your help.
my mail is lorigin @yandex .ru
phone [phone]