You can simply go for the process to check the hosting settings, simply to chuck off the QuickBooks error 6175. It is important for you to note that one or more of the systems might be set as the server for QuickBooks and the workstations can be in multi-user mode. But the server should be the only system that is set to host the mode.
Start off with, checking the windows user settings. Or add QBDataServiceUser as a user with the admin rights.
Further, check the windows firewall settings.
You can open QuickBooks on any of the workstations.
Open the file menu and also select utilities tab.
Later on, to host multi-user access options, and avoid selecting it and also move to the next workstation.
Select the stop hosting multi-user access, if available.
At last, carry out the same steps on all the workstations