I couldn't e-file with Turbotax because it said my that my Earned Income Credit prevents it to do so (don't know how that's a problem)

I paid manually online my Federal and State taxes through their respective websites.
All the post offices closed, so if I put my files inside a mailbox they'll be postmarked as the 19th. Would I get in trouble for sending the files one day late even if I already paid online (today 18th) what I owed?
Thanks!