To make sure that the firewall on your mac isn’t blocking Barcode to PC, follow these steps:

Step 1 – Open the firewall settings

Open Spotlight Search using Command + Space and type firewall

Step 2 – Click the lock and authenticate your self

Step 3 – Click Firewall Options…

If Barcode to PC server is already present in the list you don’t have to anithing, and you can skip the following steps.

Step 4 – Press the + button and select Barcode to PC server.app

Step 5 – Click Add and then OK