Links in Emails Broken, Go to Branding Domain... No Redirect

I am trying to figure out why this has happened, but the links all of my emails past and present that were sent by Marketo no longer work.  They go to the branding domain from emails, but the link stops there and brings up a 404, where it does not then go to the landing page domain.  Does anyone have an idea of why this is happening, or what could have changed.  None of the other admin level users have been in the system changing anything in the landing page or email admin sections, and overall nothing has been shifted in the admin area either.  This is now going to hold up planned campaigns, so I need to find a solution or direction quickly.