I'm currently trying to host a TF2 server on my computer using SteamCMD just as the TF2 Wiki says to. Nothing big, just a small private server for friend shenanigans.
Well no matter what I do the server refuses to let anyone besides me connect. I am able to see the server in the public and LAN lists, add it from the public IP, and connect to it with both my public and local IP. It actually works quite well in those areas, actually. I've gotten comfortable with how it works.
However it's not serving its purpose at all as others can't see it in any list, trying to add it as a favorite gives them a "Server Not Responding" message, and attempting to connect through the console gives them a "Connection failed after 4 retries" message.
I've confirmed that I've port forwarded perfectly with canyouseeme.org, and I'm able to run non-Source servers just fine so my router is forwarding ports correctly. I'm used to hosting servers like this as well as forwarding their ports but it's quite a pain when this particular one won't work for seemingly no reason. And yes, I have set sv_lan to 0.