I’ve double checked to confirm your import is still queued. It didn’t cancel. But please do reconnect to your Tumblr account if you’ve disconnected it, as that could be preventing it from starting.
We’re processing quite a few imports from Tumblr at the moment, which is causing a backlog of imports in our system. While it may look like your import failed, it’s just in line for processing, and luckily it’s still in the queue. At this point I’m not able to give an estimate on how long it might take to catch up with the backlog, though.
If you’re moving due to Tumblr’s recent announcement that they will no longer allow adult content on their service, please note that we also have restrictions on the type of mature content allowed on WordPress.com, and pornographic content is not allowed on our service at all.