I went to Tavern on the Meta and clicked "load to my last message". It responded with:
Your last message is too far back; please use the transcript instead
Click here to remove the notification bar
And it links to this message, posted May 10th:
@animuson When you print a page, just set that as the printer's test page, then print a test page.
That fixed it for me!
However, the correct message is this one, posted May 27th (yesterday):
LOL I SHOULD BE WORKING
Sorry, I thought this room deserved a message after five whole hours of inactivity.
Why can't it find the right message?