Is jupyter broken in sage 7.6?

[Stan Schymanski]

Dear all,
I just upgraded to 7.6 on Debian jessie, but when I try to run the jupyter notebook, I get the below error message. When I just run `sage` and then notebook(), I don't get any error messages. Has anyone experienced this problem as well? If not, I may try to re-install sage 7.6 instead of trying to fix the upgrade. Thanks already!

Cheers
Stan

:~/Programs/sage-upgrade$ ./sage -n jupyter
┌────────────────────────────────────────────────────────────────────┐
│ SageMath version 7.6, Release Date: 2017-03-25                     │
│ Type "notebook()" for the browser-based notebook interface.        │
│ Type "help()" for help.                                            │
└────────────────────────────────────────────────────────────────────┘
Please wait while the Sage Jupyter Notebook server starts...
[I 23:10:47.167 NotebookApp] Using MathJax: nbextensions/mathjax/MathJax.js
[I 23:10:47.591 NotebookApp] The port 8888 is already in use, trying another port.
[I 23:10:47.601 NotebookApp] Serving notebooks from local directory: /home/sschyman/Programs/sage-upgrade
[I 23:10:47.601 NotebookApp] 0 active kernels
[I 23:10:47.601 NotebookApp] The Jupyter Notebook is running at: http://localhost:8889/?token=b0a267685a1ce824e08e1d507415fa3ee14504c3806ebd58
[I 23:10:47.601 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[C 23:10:47.601 NotebookApp]
   
    Copy/paste this URL into your browser when you connect for the first time,
    to login with a token:
        http://localhost:8889/?token=b0a267685a1ce824e08e1d507415fa3ee14504c3806ebd58
Exception in thread Thread-1:
Traceback (most recent call last):
  File "/home/user/Programs/sage-upgrade/local/lib/python/threading.py", line 801, in __bootstrap_inner
    self.run()
  File "/home/user/Programs/sage-upgrade/local/lib/python/threading.py", line 754, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/home/user/Programs/sage-upgrade/local/lib/python2.7/site-packages/notebook/notebookapp.py", line 1227, in <lambda>
    new=2)
  File "/home/user/Programs/sage-upgrade/local/lib/python/webbrowser.py", line 275, in open
    success = self._invoke(args, True, autoraise)
  File "/home/user/Programs/sage-upgrade/local/lib/python/webbrowser.py", line 238, in _invoke
    stderr=inout, preexec_fn=setsid)
  File "/home/user/Programs/sage-upgrade/local/lib/python/subprocess.py", line 390, in __init__
    errread, errwrite)
  File "/home/user/Programs/sage-upgrade/local/lib/python/subprocess.py", line 1024, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

[Volker Braun]

Something goes wrong when jupyter tries to launch your browser. But if you open the URL manually it should work.