SFP+ cable won't click in all the way, advice?

SOLVED (see response below):

So I'm relatively new to SFP+ cables (I mean, you plug them in and they typically work). I have a 7M Twinax HPE cable here with standard SFP+ 10 gig transceivers on each end. I cannot plug it in all they way--it's a dead stop with maybe 1/4" of inch or a little more to go. Visually it doesn't appear any different. The opposite end works just fine, as does any other cable, in other ports and NICs, so I've done all the obvious troubleshooting. Before I contact my vendor and say "no worky," I'm curious if others have run into this and I'm missing something that once you know the secret handshake you're allowed into the room for the cocktails. Any advice is appreciated!