Won't canter!

Since he is a showw horse continuous sweezing might just mean extend more and more since you don't know his cue to canter I would bring him back to a lounge and teach him kiss means canter untill everytime you kiss he we auto go into a canter then try the same thing with riding him

Like its already been said... make sure your asking him properally, not pulling on his mouth etc. If he is a show horse and has had training then he should canta, although it could be a stubborn thing like you said. Either way, I wouldnt let it continue. If he doesnt listen to your aids, then maybe a artifical aid like a whip or spurs may help.

I will certainly try. I'll let you know how it goes.

I was taught in a round pen to canter......ask for it in the same place every time....trot nice and forward. Before you ask for canter, stop posting, sit the trot a few strides, lift your energy, outside leg goes back behind girth, good squeeze, "cluck" or "kiss" sound loudly and firmly and if no canter, "spank" or tap with whip or crop. If he's not responding to your leg aid, you need to follow it up with a crop or whip. Once he gets this, you probably won't need it any more....always ask in the same place, every time. I was never taught to pull or adjust either rein when asking for canter. Just point him in the right direction and ask with sitting trot and outside leg back....and I sort of urge him forward with my seat. If you don't sit a stride or two and keep posting, he may still think "trot".

It can help to sit trot down the side of the arena before you canter, it gives the horse time. (dont think that will help sorry)

Make sure while cantering that you aren't posting. That usually inhibits the horse to canter. What I do, for my guy, is I'll give a "cluck" or a "kiss" and then give him a little squeeze with my legs. If he doesn't canter and just speeds up, I'll slow him down for I don't want him to learn that the cue means to do an extended trot. Then I try again, this time I'll "cluck" or "kiss" and then give him a slight kick.

Also what I've seen also, in some horses (YES I know this is the wrong way, but it might be worth a shot to get your gelding used to cues) that if you are trotting, and then lean up into jumping position or somewhat in jumping position they'll take off in a canter...at least mine does.

Don't be too afraid to use the crop. The crop is a re-enforcement of your legs. Ask for the canter, say "canter" (if that's what you say to get him to go) and then give him a slight kick with your legs. If he doesn't go, slow him down into a regular paced trot, then ask again, this time kicking just a tad bit harder. If he still won't go ask for the canter and then kick him a slight tap with the whip...and keep getting harder until he goes.

He might be testing you...I had a horse that wouldn't canter for me and I'd keep trying to canter her, but she would only speed up...so finally I gave up and just trotted around. Finally I got so annoyed that I kept at it until she cantered.

Your horse might just be lazy and not like to canter, so he could be giving up a fight