Unable to connect to opentsdb as a backend storage

I have graphite webapp installed and using opentsdb as a backend storage via https://pypi.python.org/pypi/graphite-opentsdb/0.4.1.

I had this working but all of a sudden, it stopped working. I keep getting these errors. It sounds like the data that opentsdb returns, graphite unable to read it. I verified that opentsdb returns json formated data. Any ideas what might be going on here?

[Mon Apr 20 18:05:43 2015] [error] ValueError: No JSON object could be decoded
[Mon Apr 20 18:11:13 2015] [error] Internal Server Error: /metrics/find/
[Mon Apr 20 18:11:13 2015] [error] Traceback (most recent call last):
[Mon Apr 20 18:11:13 2015] [error] File "/usr/local/lib64/python2.6/site-packages/django/core/handlers/base.py", line 112, in get_response
[Mon Apr 20 18:11:13 2015] [error] response = wrapped_callback(request, *callback_args, **callback_kwargs)
[Mon Apr 20 18:11:13 2015] [error] File "/opt/graphite/webapp/graphite/metrics/views.py", line 128, in find_view
[Mon Apr 20 18:11:13 2015] [error] matches = list( STORE.find(query, fromTime, untilTime, local=local_only) )
[Mon Apr 20 18:11:13 2015] [error] File "/opt/graphite/webapp/graphite/storage.py", line 47, in find
[Mon Apr 20 18:11:13 2015] [error] for node in finder.find_nodes(query):
[Mon Apr 20 18:11:13 2015] [error] File "build/bdist.linux-x86_64/egg/graphite_opentsdb/finder.py", line 120, in find_nodes
[Mon Apr 20 18:11:13 2015] [error] for node in find_nodes_from_pattern(self.opentsdb_uri, self.opentsdb_tree, query.pattern):
[Mon Apr 20 18:11:13 2015] [error] File "build/bdist.linux-x86_64/egg/graphite_opentsdb/finder.py", line 45, in find_nodes_from_pattern
[Mon Apr 20 18:11:13 2015] [error] nodes = list(find_opentsdb_nodes(opentsdb_uri, query_parts, "%04X" % opentsdb_tree, shared_reader=shared_reader))
[Mon Apr 20 18:11:13 2015] [error] File "build/bdist.linux-x86_64/egg/graphite_opentsdb/finder.py", line 59, in find_opentsdb_nodes