hello,
@alexm you should look what responses you are have from PayPal.
Enable debugging in your config/environments/development.rb
:
config.after_initialize do
# change log level to DEBUG
PayPal::SDK.logger = Rails.logger.clone
PayPal::SDK.logger.level = Logger::DEBUG
# log all PayPal requests
PayPal::SDK.configure({verbose_logging: true})
end