I neglected to check (or wasn;t awake at the time) the pap
auth check box when I added a ppp interface. Entering the
pap login name and password still prevented my logining into
my isp. The only solution I could find was to delete the
ppp0 interface and re-create it this time checking the "Use
PAP" check box.

Also - usernetctl now complains about users (even root)
using it... the 5.1 docs suggest this be used, but 5.2
doesn't mention it at all... I finally stumbled upon usernet
which allowed me to activate the interface.