Thanks all. As an update, the lock didn’t work with the bar pushed into the U. It didn’t work with the bar pulled out of the U (a little, a lot, medium). Somehow, after trying for 5+ minutes Sunday night, Monday morning and Monday evening, right as I was about to walk over to the neighbors to see if they had some WD 40 (we haven’t unpacked our garage yet), I slipped the lock over the vertical bar of the bike rack, pulled it out a little and it worked! (There’s no way on Earth that it mattered whether it was diagonally across that vertical bar or parallel to it).
Anyway, I’m planning to contact On Guard today to see about a replacement. I think we’ve only had this puppy since December.
Thanks all!
G