You shouldn't need to change the domain name.
On the Embedding Options Screen you should see two sections, the first headed "Javascript code". The second takes one of two forms.
If the forum is not embedded (i.e you have not used the JavaScript code to embed your forum):
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Redirect Users
Redirect options are available only when the forum is embedded.
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And will follow this patten once embedded:
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Redirect Users
Your embedded forum is hosted on Nabble at this URL:
http://myforum.123456.n1.nabble.com/( ) Allow users to view this forum without embedding.
(•) Redirect them to:
http://www.mysite.com/targetpage.html-------------------------------------------
If you are seeing the first type pattern then it sounds as if something is wrong.
Volunteer Helper - but recommending that users move off the platform!
Once the admin for GregHelp now deleted.