There is an option to automatically allow signed software to receive incoming connections. This means the NVMS2.0 apps and services signed by a valid certificate authority will automatically added to this list. Any app that is created by Apple, for example, that needs to receive incoming connections will be automatically added to the list. If NVMS2.0 can not connect to devices successfully, the firewall may be blocking the network access of NVMS 2.0.
Blocking all incoming connections will “prevent incoming incoming connections to nonessential services and apps.” This means that the firewall allows your Mac to find authorized services provided by other computers on your network, but prevents connections to all other sharing services.
Click on the Apple icon and select "System Preferences"
Click "Security & Privacy"
Select "Firewall"
Select "Firewall Options"
You may need to click the lock icon to make changes to the setting. You will be prompted to enter your Mac OS credentials.
Select "Firewall options"
You will need to allow connections on the services listed in the snapshot below. Press "OK" to confirm.