I've been having the same problem. Always, around 30 minutes of being ingame, all account but one will close out.  I know my pc has pretty bad specs, but this only started happening recently. Also, unrelated to multirblx, but joining any game for me has become difficult, as I will constantly have "trouble verifying" or an "http error" on most of my joins, the issues could be related. My friend who also uses multirblx does not have this error.