1) make sure the actual mount is secured properly (surface was clean when you attached it, you pushed it on long enough and gave it time to dry (on room temp.)
2) if the mounting foot is loose inside the actual mounting plate, push the rubber orange thingy in, this is to prevent vibrations
3) if the foot is still vibrating, take a small twig from a tree (almost always available) and wedge it underneath the camera, this will secure it nicely!
(i have this too, but only on my longboard mount because it gets sand in the mount and it erodes the base so it became all loose; now adays i just jam a small twig between the foot and mounting plate.... + rubber orange thingy....