I don’t know if you will answer and personally I don’t even care about going private anymore because this site is dead now. The option to download your tumblr into a zip file is not working, the link brings you to a blank page. Did I miss my chance to do that because my explicit content was already flagged, or is the server overloaded right now, or...? I didn’t get any answers from googling it and you seemed to know most about the tumblr ban so I thought I would ask you.
It works fine but you need to be aware of (1) your network speed and (2) your web browser and (3) Adblock software.
You should get an email from Tumblr telling you to click a link and it will start downloading. Check to see if it was blocked first. Maybe copy the link into Chrome or Safari. If you can, plug your computer into your router to increase your bandwidth. Internet Explorer is horrible and sometimes Chrome for timing out if a download takes too long to complete. Maybe install Opera, Safari, or Firefox and use try those browsers. If your blog is extensive, it will take awhile.
It could also be Tumblr servers are in maintenance or being hit hard but they likely use a cloud-based server farm that should handle spikes so it may be slower, but not to the point it fails.