Urbackup GUI no accessible (loading forever)

Check IPTABLES/FIREWALLD (firewalld uses iptables, so don't change iptables manually)

Allow https via firewalld

 firewall-cmd --permanent --add-service=https

 firewall-cmd --reload

 firewall-cmd --list-all

 windows PC ping icmp not working

Windows Firewall -> Inbound Rules -> allow icmp.

Also, if the interface in Network of Windows is marked as “public” instead of “work", then it makes Windows think it is on a public hotspot and it will not give access remotely even if the windows firewall rules allow it (In “Public”-mode it doesn’t read the “Inbound Rules”…)

 Change the interfaces to “Work” or "Private"

In windows defender:

1. Search for Windows Firewall, and click to open it.
2. Click Advanced Settings on the left.
3. From the left pane of the resulting window, click Inbound Rules.
4. In the right pane, find the rules titled File and Printer Sharing (Echo Request - ICMPv4-In)
5. Right-click each rule and choose Enable Rule
6. change remote "local subnet" to "any"