Command /home/docs/checkouts/readthedocs.org/user_builds/brainconn/envs/latest/bin/python -m sphinx -T -E -b html -d _build/doctrees -D language=en . _build/html failed: Running Sphinx v1.8.6 loading translations [en]... done Traceback (most recent call last): File "/home/docs/checkouts/readthedocs.org/user_builds/brainconn/envs/latest/lib/python2.7/site-packages/sphinx/cmd/build.py", line 303, in build_main args.tags, args.verbosity, args.jobs, args.keep_going) File "/home/docs/checkouts/readthedocs.org/user_builds/brainconn/envs/latest/lib/python2.7/site-packages/sphinx/application.py", line 228, in __init__ self.setup_extension(extension) File "/home/docs/checkouts/readthedocs.org/user_builds/brainconn/envs/latest/lib/python2.7/site-packages/sphinx/application.py", line 449, in setup_extension self.registry.load_extension(self, extname) File "/home/docs/checkouts/readthedocs.org/user_builds/brainconn/envs/latest/lib/python2.7/site-packages/sphinx/registry.py", line 472, in load_extension mod = __import__(extname, None, None, ['setup']) File "/home/docs/checkouts/readthedocs.org/user_builds/brainconn/envs/latest/lib/python2.7/site-packages/m2r.py", line 59, in <module> class RestBlockGrammar(mistune.BlockGrammar): AttributeError: 'module' object has no attribute 'BlockGrammar' Exception occurred: File "/home/docs/checkouts/readthedocs.org/user_builds/brainconn/envs/latest/lib/python2.7/site-packages/m2r.py", line 59, in <module> class RestBlockGrammar(mistune.BlockGrammar): AttributeError: 'module' object has no attribute 'BlockGrammar' The full traceback has been saved in /tmp/sphinx-err-qceopZ.log, if you want to report the issue to the developers. Please also report this if it was a user error, so that a better error message can be provided next time. A bug report can be filed in the tracker at <https://github.com/sphinx-doc/sphinx/issues>. Thanks!