Official support of the block bot has ended, however you can sign up using one of the blocktogether lists below -
Level 1 -> https://blocktogether.org/show-blocks/0e486a43dd4e2a7f5f5938a1fefd0a39a884d405e76601e213f3e8dc1981608af2db331d38fefbcb8a08642b320c0982
Level 2 -> https://blocktogether.org/show-blocks/096e933c1b0f6e188e2acc9e037b1822a90ac3b77274de0e4bd1387cbf06430aa642b23b67c4123b2b290d9c590a2120
Level 3 -> https://blocktogether.org/show-blocks/2389dcfee4b4022a790f01d8a6322fdca59e21347e80964393be96706465099fc820402a7370f6277833d7d689f9b3de
@oolon and the previous admins DO NOT provide any recommendation or guarantee for these lists. They are now out of our control, check @TheBlockBot on twitter to see who is adding / removing and check the lists for erroneous additions. The old levels will presumably be maintained, with the worst people added to level 1, middling level 2, and more annoying but bigoted to level 3. The descriptions are in the old blockbot introduction linked below.
If you are a previous user of the Bot you might want to disable the app in Twitter and sign up to one of these, depending on what level you want to block at.
Old BlockBot FAQ -> http://archive.is/T48BG
Old BlockBot Introduction -> http://archive.is/WJ19U
@oolon's blog post explaining the change -> https://itperformance.xyz/2018/02/20/theblockbot-into-the-sunset/