Occasionally, due to a potential variety of factors (e.g. wet parts, heat, cleaning conditions), the valves can pop off the top of the lids while you're trying to assemble them.

Two quick fixes:

(1) If wet, dry off the valve and the bottle.

(2) Ensure a complete seal between the valve and bottle by running your finger along the edge.

Still having issues? Email or call - support@moxxly.com, (509)985-8092.