3 possible reasons come to mind.
The home router issue can be ruled out by connecting the PC directly to the internet modem. Then reboot the internet modem to assign a new IP address.
While directly connected to the cable modem type 'ipconfig' into Windows command prompt and write down your IPv4 address. You can use this to check if your ISP uses carrier grade network address translation (CGNAT). If the IP address starts with 100. Then your ISP uses (CGNAT) and is blocking incoming connections from reaching you.
If you still can't connect then it's either an ISP or Windows firewall issue.
