Hello,
We just encounter this issue yesterday, looks like something wrong with GoogleAds api or refresh_token permissions.
So we are working as a company with a hierachy Adwords accounts: Main account => MCC account (for different countries) => single account.
We are using both python/php googleads api for user authentication and store refresh_token/access_token to build our in-house BI tools.
Yesterday, we found any user with standard access to MCC account after authentication (2 step verifcation completed), having an refresh_token that not working.
Even when we try to generate refresh_token using Adwords OAuth2 Playground, the issue still the same.
It is throwing this exception when we try to get list customer from account:
googleads.errors.GoogleAdsServerFault: [AuthorizationError.USER_PERMISSION_DENIED @ ; trigger:'<null>']
Another note, this is working fine for users having access to top account (the account that has access to all MCC account).
Can you please check, or let me know if other details needed.
Thanks,
Sang