A friend created a vanilla server in the latest version. (26.1.2) He and another friend joined, and then when i tried to join, it just endlessly said "Connecting to server" then I got a "getsockopt" error message, which sent me back to the multiplayer screen. My friend restarted the server, and suddenly i could join, but our other friend started getting the same "getsockopt" error. This happened a couple times, where he could join and I couldn't, and then I could join but he couldn't. We didn't put in any mods, nor special settings. Vanilla minecraft, new server on aternos without any special config except "cracked". I have tried both the official and non-official launchers and get the same error on both.
Edit: I've used the normal IP, the IP with the port and the DynIP. The error is the same in every one.