Problem with Spam & Testing

Last Friday I sent out a campaign for a client to all of the employees. The campaign went through just fine and almost all of the employees opened the email and clicked the links. None of the emails went to spam. I am sending the same campaign today to a list of customers. I am trying to test the email by sending it to an email address with the same domain as Friday's campaign. Now the campaign is going into the Spam Quarantine. It's the exact same campaign (same images, same wording, same from address). I've setup all of the custom domain and keys to ensure that it's coming from my domain and not campaign monitor. I can't figure out why it worked Friday and it's not working now. If I send a test to an email outside of the domain I sent to last Friday, it works fine! Please advise as this is very puzzling.

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