mciroRNA.org service is not working for several months. I do not know the reason. It was a beneficial database and I counted on it for one paper, but during editing, it became unavailable anymore. However two weeks ago, it was surprisingly opened by chance for just a day, then it is not available anymore. I tried contacting the developers but not receive reply.
I encountered the same problem accessing the tool, turned out that it is just a simple conda install. If you want to use it make sure you run it in a virtual environment, to prevent conda from messing with your other packages.