Cannot place a ground

Hello I am new to this forum. I am quite desperate for help. I have been using Pspice since the beginning of Fall and have never had this problem before. I cannot place a ground, regardless of how simple my circuit is. When I click on the ground button nothing happens. The user manual has no information on this, and neither does the website. I also cannot find anyone else who has had this problem on the internet. Any help would be greatly appreciated. Thank you!