Error: "Sorry, there was a problem!"
Google Chrome browser
We can suggest the user try to connect in "Incognito" browser mode, in Google Chrome browser it can be opened by hotkey combination "Ctrl" "Shift" "N" (incognito mode)
Once in incognito mode, please sign in to LodgeiT => select the required organisation => click "Connect to QBO" => the user will be redirected to QBO page => Sign in to QBO => select the required QBO file to connect.
Try to sign in "private" browser mode, in Firefox it can done by opening "New private window" from browser menu
Usually, this error occurs because of old cookies in browser. If it helped, to make it work in a regular browser mode it's necessary to clear browser cookies and cache.