I am having the same issue on a PVE dedicated server I have with my friend. I don’t think it’s mod-related because I had him check just now, he is not having any issue at all using left click to build or anything in the server. But for me, I had to change the key binding to something else to place anything or build. I tried dying, deleting my character, and restarting server. Left click was working an hour ago and just suddenly stopped. Map Isle of Siptah. Also tried both admin/creative mode and regular, left click not working to do any in-game functions either way (like OP, left click in menus etc. works)