Unfortunately, it still failed to connect.

In your inbound rules, there should be four entries:

- Valheim TCP, Specific Ports, 2456-2458 (or whatever you're using)
- Valheim UDP, Specific Ports, 2456-2458 (etc)
- Valheim TCP Server, D:\steamlibrary\steamapps\common\valheim dedicated server\valheim_server.exe (or whatever your path is), All Ports, TCP
- Valheim UDP Server, D:\steamlibrary\steamapps\common\valheim dedicated server\valheim_server.exe (etc), All Ports, UDP

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Can you give me the link where you got your Dedicated Server setup guide?

Also, can you check again your external IP address my typing My IP in the search and see if it matches the one you posted above?

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Basically, if you are buying internet service that doesn't give you a dedicated IP address, then your external IP may change if your router/modem is powered down or resetted. Also, your dedicated host company may also have its internal IP change every time you restart the computer.