Isn't this a half model?  I added a Symmetry BC like this.

Turned on Weak Springs to mitigate the Near Open Contact Tool Initial Results.

You didn't move anything in CAD to close the gaps. You must move the parts in CAD until the boss/head is touching the hole/face of the rigid link on both ends. Since there is clearance, only one face can touch. Due to the direction of force, the green part will push on the bone side of the dark grey part and the other end will push on the boss side of the light grey part.