My Node is OFFLINE for 2 hours

Please, compare the WAN IP and public IP with the address in your ADDRESS option.
If you use the DDNS address, then check it (please replace the ddns.address to your actual DDNS address)

nslookup ddns.address 8.8.8.8

, it should return the same IP as your WAN IP on your router and public IP on yougetsignal.
Also, if you are on Windows, please add a firewall rule: