Sometimes get get the following error while connecting to a multiplayer game (also had this in version 14). Going to the multiplayerscreen and try connecting again, works just fine.
1.) Open "Browse Public Games"
2.) Select a muliplayer game to join. (do not connect)
3.) Wait around 1 minute, till you see at the bottom, the "refresh" bar complete.
4.) Press join game, on your selected muliplayer game.
If you reselect the game in step 4, before connecting, then you can connect.
Seems like that after the refresh happend, the selected muliplayer game loses it attributes.
Today i found out a reproducable way to get the error every time when connecting to a multiplayer game.[0.15.10] Notice: SentTo (0.0.0.0:34197) failed
Re: [0.15.10] Notice: SentTo (0.0.0.0:34197) failed
I believe that's telling you that the selected server is no longer valid to connect to because you waited too long to hit connect.
If you want to get ahold of me I'm almost always on Discord.
Re: [0.15.10] Notice: SentTo (0.0.0.0:34197) failed
The Notice Text is in Dutch, translated to english: "The requested address is not valid in its context of the adress"