acces token Types on oauth flows

Hello.

I'm a developer and I'm trying to authorize myself for letting other users manage their MS Advertising accounts. I have two different accounts and I can login to their respective MS Advertising accounts. I work in an organization and do not know the configuration, scope or permissions granted of any of the accounts further than what they told me witch is that "I have all permissions required". I can get authorization without problem with one of my accounts, but not with the other. I'm following this guide and with the working account i get an acces Token like "M.C547_BL2.." and got the Refresh token without problem. With the other account, thought, I get an access token that starts with "1.ARIAQ..." once I try to get the Refresh Token I receive and error from the API saying that the value for the code is invalid. Searching online, I read that this may be caused when one of the accounts is used in several MS services while the other one is configured only for MS Ads. As the process followed is the same for both accounts, what should I do for getting oks for both of them?

thanks and regards.