Launching Draftsight Professional 2019, I get "Cannot obtain a license for Draftsight...." and zero help

I have a seat of Draftsight professional that I purchased in December last year. I have been using it continuously since then.

This afternoon (1700 edt) I launched it to do some work and got this (see attached). After clicking OK, the program exits. There is no further information. anyone come across this one?