If you want to share folders with other computers make sure that your local network is cataloged as a trusted network in the firewall configuration.
Follow these steps to check it:
Click Status in the main menu.
In the Protection section, click Settings.
Select the Firewall option.
In the Networks section, click Settings.
Select the network you want, if there is more than one, and click Settings.
Make sure that the trusted location option is selected.
You must check this on every computer that you want to connect across the local network.