NuBitsexplorer.nu should work again now. Restarted Nu daemon again as it crashes 2-3 times a week. Desperately waiting for v2.1 to get a more stable environment. It is most likely due to memory issues as many have experienced by now.
Edit: takes a while to sync again though.
Edit2: Apologies, you are referring to the other blockexplorer. That is frozen indeed and also needs a restart @coingame. Possibly suffering from the same problem.