There are a couple common mistakes people can make in situations like this. One is they forgot to install the screw holding the battery connector or didn't secure it enough. The second is they may have damaged the battery connector on the board if they inserted the pry tool, which may require replacement. That can happen if you insert the pry tool directly into the battery connector. It's recommended that you insert the tool next to the battery connector.
Double check to make sure you put that battery connector screw back in place and it's secure. If that doesn't resolve the issue, you're going to need to lift up the board enough to get a look underneath so you can see the battery connector.