Created attachment 1593433 [details]
Image of the Cockpit screen with error message

Description of problem:

When trying to add a custom port to firewalld using Cockpit interface, it fails with error:

Failed to add service
Error message: org.freedesktop.DBus.Error.InvalidArgs: Too few values in tuple/struct


Version-Release number of selected component (if applicable):
Red Hat Enterprise Linux 8.1 Beta
cockpit-system-196-1.el8.noarch


How reproducible:
Always


Steps to Reproduce:
1.Access Cockpit interface using an user with root privileges
2.Navigate to Networking->Firewall->Add Services->Custom Port
3.Input TCP port number, for example, 3000 or 8080. Click "Add Ports"

Actual results:
Error message:
Failed to add service
Error message: org.freedesktop.DBus.Error.InvalidArgs: Too few values in tuple/struct


Expected results:
TCP Port would be successfully added to the firewall rules


Additional info: