In case anyone else is having this issue, it turns out it was something obvious. There was nothing wrong with our footer - for some reason our Footer was set to "None" in delivery profile options for our selected Send Classification.
We are trying to send out our first Marketing Cloud email and are faced with this message when we try to preview and test the email in question. I have been back & forth with SF Support, opened 3 different cases but still have not had this issue resolved. In the Subscriber Preview and Attributes section of Preview & Test (for any email), we are met with the following error upon selecting any subscriber. SF Support has checked our footer and it's attributes (Profile center link, unsubscribe center link, physical mailing, etc...) and everything is formatted properly.
If we disable the Profile Link/Physical Address/Unsubscribe Link Checks in Email Optional Features, the email sends through OK but of course without the footer.
SF support has told us that the error they're seeing in the backend: Missing_Profile_Center_Link Missing_Profile_Center_Link %%Member_Addr%% %%Member_Addr%%
When we try to send the email to our data extension (not a test), we are immediately met with a "Failed" status - SF support said there was nothing wrong with our targeted DE.
What could be causing this error? Is it something wrong with our subscriber info that's causing this error to pop up upon selecting a subscriber in Preview in Test? I've read through all of the docs but cannot find a solution, hopefully it's something obvious that I'm missing.