I cannot log into Facebook when logged in via the settings screen of iOS

When not logged into Facebook via the system settings, everything functions fine. However, I cannot log into Facebook through the Prime31 plugin when I am logged in already via the system settings.

Under the option "Allow these apps to use your account", my app is listed and is enabled. In the app itself, when I press the log in button, a dialog pops up stating: "[App name here] would like to access your basic profile info and list of friends" with the options 'Don't Allow' and 'OK'. I press the OK button, and the function "loginFailedEvent" is triggered.

In my function that calls 'init', I have this line just after it:

 FacebookBinding.setSessionLoginBehavior(FacebookSessionLoginBehavior.UseSystemAccountIfPresent);

This is what is logged in XCode:

session creation error: Error Domain=com.facebook.sdk Code=2 "The operation couldn’t be completed. (com.facebook.sdk error 2.)" UserInfo=0x1aa7bc80 {com.facebook.sdk:ErrorLoginFailedReason=com.facebook.sdk:SystemLoginCancelled

Any help is appreciated.