Thank you for reaching out to Constant Contact's API Support.
Generally that message is relating to the entire email address and not just the domain, unless the domain has a problem in it, and I do not see any problems in the domains you've listed.
In order to properly troubleshoot this I would need some more information and the information that is needed might be best if it is kept private. You may want to reach out to us at firstname.lastname@example.org.
Can you please provide the API Key and Constant Contact username you are using as well as the full email address that you are submitting along with the endpoint you are submitting when the error is being generated. If you are using a specific bit of code then a code sample would be good as well.
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