Both remotes opened my garage door opener until I changed the batteries in one. Now I can only get one remote to work at a time. I can't get both programed at the same time. Any suggestions.
One of your remotes has reverted to an earlier technology and although they will each work individually they will not work together. You need to purchase a new remote of the same model number you have and you will find that the new remote will work with one of your remotes but not the other. Remove the battery from the bad remote and discard it to prevent problems down the road.