Stop hosting multi user

I am using a third party CISM app that is connected to Quickbooks and something is interfering and disconnecting the app while it's syncing. I changed the setting to allow the application to log in automatically but that makes it worse now. Something else is trying to access Quickbooks and multiple windows open up asking for admin access. I used to have a multi user but don't need it anymore. I stopped hosting multi user on this computer but it keeps changing back to hosting. Not sure if that has something to do with it, but there is definitely something running in the background that is conflicting with the CISM and I can't figure out what. Hoping someone has some suggestions?