In the code, the map will add a script that looks similar to this:
The "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" is where the api key is stored. Make sure you replace that with the one that was generated for your new domain. If it isn't working, try going back and generating a new api key, it may not have been generated correctly the first time.
And if you could elaborate on the not being able to edit the api key in the interface issue, that would be helpful.