That totally sucks balls, hopefully you didn't fry the OT. It's always good practice no matter if a cab is new, used $50 or $2,000 custom or mass produced to check its impedance out the jack before ever hooking up, especially to a tube amp. That way you can have it figured out before ever hooking it up and powering on if somethings not right. I put my faith in no one and anything can happen in transit. The same goes with a new or new to you tube amp, always make sure the tubes are seated completely and properly before powering on for the 1st time. But that's all hindsight right now. I wish you luck and hope it's something stupid simple you overlooked. I love that blue snakeskin BTW.
EDIT
Just saw your newer post. That terminal pulled back a little is probably what they are referring to. If you have a multi meter check continuity from the jack blade it's attached to and the other end of cable hooked to speaker and wiggle it around while doing it. if it buzzes out and doesn't cut out at all then that's not the problem. Those don't need soldered anyways if they are the proper size for the blade.