Server Help Specifically one friend cannot connect to my server

My friend just reinstalled the game the other day to play since 1.0 will be out soon, and wanted to play online. I set up a server with he and another one of my friends, but while my other friend and I can connect just fine, one of my friends cannot seem to connect. We've ensured several times he's entering the correct information, we're all using the most recent stable version of the game, and the server's max players should allow him. Obviously, he's not banned either.

Any ideas as to why this may be? Has anyone else experienced a similar problem? It's also worth noting that nothing shows up in any of either of our logs showing any issues aside from that the connection failed (on his end, I get no message).

 

I have had this happen. I was on the "cannot join" end. Unfortunately, never found a solution.
Even though you already did this, I'd suggest reinstalling the game - and I mean deleting everything, even if files remain in its directory.
And while none of these things are perfect, perhaps try a VPN like Hamachi for connecting? It may or may not help, assuming you aren't already using one.

 

I have tried new things to get my friend to connect to the server, it unfortunately has not worked yet.

• I've tried deleting my player / universe folders, ensuring that the universe is freshly generated.
• I opened and forwarded ports 21026 and 21027 on my router and windows firewall (in addition to 21025), I didn't change any starbound config files, but I assume since these are the defaults, I shouldn't have to. (I don't even know what an rcon server is..)
• We tried having my friend start a singleplayer game with his freshly created character, or creating a new character just for the server. Neither worked.
• We've tried having my friend connect without using a port and with using a port, neither works.
• We've also tried with or without a password being set for the server. Neither works.

In all of the above instances, both myself and another friend (in a different state) can connect to the server using my external IP address and no port entered, but the other friend cannot. I've urged him to reinstall the game, and I'm curious if he would be able to connect to other multiplayer servers. If there's any information out there about players who cannot connect to multiplayer servers, or a fix that's been found for that, I'd like to know! It also goes without saying, of course, that his copy of Starbound is legitimate. In fact, he purchased a 4-pack and one of the copies he purchased was for the other friend who can successfully connect.