Use grease if it's an alloy frame. Use carbon friction paste if it's a carbon frame. Carbon frames shouldn't be torqued tighter than 5-6 nM! The friction paste helps it grab at low torque. Too much grease shouldn't make a difference if it's an alloy frame. A bad or wrong clamp could be responsible as mentioned or a shim is missing, also mentioned earlier. If you have to tighten the bolt too much, you may hinder the rise rate of the post. Besides the Salsa clamp, Wolf Tooth's also has a self-centering bolt to help torque better.
EDIT: if the post is the wrong size, the bike could've been assembled with a beer or soda can shim by the shop who was in a pinch (there are nice lipped shims for this purpose) I had this done on an old bike but didn't know it until I went to adjust the post. I found I had shoved the shim down into the tube so it was no longer grabbing the post. Fished it out, wrapped it around, reinserted--perfect fit again.
Last edited by bikeme; 04-19-20 at 05:11 PM.