iirc the region setting for the characters you launch from ISboxer is wrong:
In your \World of Warcraft\WTF directory you should see a whole load of .wtf files. One will be called just 'config.wtf' and the rest will be called something like 'config-<character name>-<server>.wtf', one for each character you have setup in ISboxer
Open the config.wtf with notepad and take note of the line that begins "SET portal" (this is the line that tells the client which regions servers to connect to - EU, US etc)
Now open the .wtf file for one of the characters that will not launch from ISboxer and make sure the 'SET portal' line is the same as config.wtf - this should fix it
Apologies if that goes to too much detail, you said you were new so didn't wan't to presume anything
PS In next week's episode I will try to remember how to stop it happening in the first place, you likely need a new game profile set-up for WoW but let's make sure that is the problem first
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