Just put a small retaining wall with capstones, and am having problem getting the adhesive to set. Ive tried a couple different types. General masonry adhesive, which didnt work. Followed that up with Liquid Nails for concrete/masonry. Which also didnt work. Im thinking it must be the weather. We've had a recent run of cool-cold temps with rain every 4 or 5 days. What would you suggest?