Tumblr got back to me and after some troubleshooting, they confirmed that yes, there seemed to be a glitch in my admin panel yesterday.
But I woke up just now, and am able to publish and “Pin” posts again. Yay! So here’s my own guess as to what happened:
I concluded that maybe Tumblr has a 1-pinned-post-per-day system in place for SPAM purposes (totally cool and would make perfect sense). But perhaps when my transaction had a glitch and never published, the website assumed that it had, and therefore wouldn’t let me retry to post it. So I had to wait another day until the 24-hour clock “reset” itself.
Like I said, that’s just my own guess as to what happened. I promised I would keep you all informed, and I appreciate your patience (and Tumblr Support’s quick help yesterday).
But enough about that - let’s just get to the music!!! That said, if all goes well then the song should go live today!