Starting yesterday I am getting a 403 response from the legacy post endpoint. I have not changed anything in my script, so I am assuming something changed on Tumblr's side.
response body:
<html>
<head><title>403 Forbidden</title></head>
<body>
<center><h1>403 Forbidden</h1></center>
<hr><center>nginx</center>
</body>
</html>
I created a support request (11204987) as well, but I've only gotten a response from the AI so far.