I just got a horse that said it belongs to {0} and I got him to one of my claims and used a saddle to claim him but I can't ride him please help.
Have you tamed the horse yet? That may be your problem, however, I don't think you can put a saddle on a horse without it being tamed..
This is because you are trying to mount the horse in someone else's claim. Horses are protected inside claims, so walk outside the claim, teleport your horse to you, then get on.
Either, you got a horse from a person who had owned it previously, or what c0w said. Are you able to get on the horse at all? (meaning anywhere)
I still can't get on the horse even in my pasture c0w. Abbz I can't get on it anywhere he is claimed by me. When I try to ride him it says, " ??c You are not allowed to ride this horse!". what could that be?
Please ask a helper or moderator to help you when you are online. It's difficult to diagnose a problem like this unless you are in game trying stuff. I still believe that you are not in your claim when trying to get on the horse, but I can't say for certain.