I'm using the default servers.ini for this, and I can make that conclusion because the ports it's trying to connect on in that log snippet are not listed for that network in the file (only 6667 and 7000). I gave that info in my reproduction steps further up.
Also this issue might not apply when using /server. I used the options dialog for all of this, clicked select for the networks and then just clicked the connect button in mIRC.
