Jupyter TensorBoard extension error

[winnielin]

jupyter-tensorboard 0.1.9
tensorboard 1.12.2
tensorflow 1.12.0
tensorflow-tensorboard 1.5.1

[E 15:49:41.504 NotebookApp] Couldn't parse JSON
Traceback (most recent call last):
File "/Users/winnielin/anaconda3/lib/python3.6/site-packages/notebook/base/handlers.py", line 494, in get_json_body
model = json.loads(body)
File "/Users/winnielin/anaconda3/lib/python3.6/json/init.py", line 354, in loads
return _default_decoder.decode(s)
File "/Users/winnielin/anaconda3/lib/python3.6/json/decoder.py", line 339, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "/Users/winnielin/anaconda3/lib/python3.6/json/decoder.py", line 355, in raw_decode
obj, end = self.scan_once(s, idx)
json.decoder.JSONDecodeError: Unterminated string starting at: line 1 column 11 (char 10)
[W 15:49:41.508 NotebookApp] 400 POST /api/tensorboard (::1): Invalid JSON in body of request
[W 15:49:41.509 NotebookApp] Invalid JSON in body of request
[W 15:49:41.509 NotebookApp] 400 POST /api/tensorboard (::1) 8.51ms referer=http://localhost:8888/tree/Dropbox/Postgraduate/Module/(1%262)%20The%20Masterclass%20in%20Business%20Analytics/Files%20from%20Gerons%20book%20(shortened)