when try to get clients list the ruby wrapper returns:
CreateSend::Unauthorized: The CreateSend API responded with the following error - 50: Must supply a valid HTTP Basic Authorization header
I use an api token returned by omniauth authorization flow that have only 'ManageLists' as scope, maybe is this the problem?
Any idea to resolve this issue?
ManageLists should be sufficient scope for accessing the lists of a client, and in any case if the scope is incorrect you'll be returned a different error message. So something else is going on here.
My "most likely" guess is that you're not constructing the Authorization header correctly. Are you using the createsend-ruby wrapper and constructing the auth object like this?
You might want to post a sample of your code (obfuscate any tokens/keys first) or send us through a support request so we can take a closer look.