OSError: Address "" already in use.

Hi all!

I’m running into an error when trying to run app.run_server(mode='external')

Even if I kill all ports, and even if I change the port to a random number (for instance: app.run_server(mode='external', port=2000)), the error still persists. I don’t know how to resolve this. Help would be appreciated! Thanks!

Full error:

---------------------------------------------------------------------------
OSError                                   Traceback (most recent call last)
<ipython-input-5-0a3a9f2580ba> in <module>
----> 1 app.run_server(mode='external', port=2000)

/opt/anaconda3/lib/python3.7/site-packages/jupyter_dash/jupyter_app.py in run_server(self, mode, width, height, inline_exceptions, **kwargs)
    317                 )
    318 
--> 319         wait_for_app()
    320 
    321         if JupyterDash._in_colab:

/opt/anaconda3/lib/python3.7/site-packages/retrying.py in wrapped_f(*args, **kw)
     47             @six.wraps(f)
     48             def wrapped_f(*args, **kw):
---> 49                 return Retrying(*dargs, **dkw).call(f, *args, **kw)
     50 
     51             return wrapped_f

/opt/anaconda3/lib/python3.7/site-packages/retrying.py in call(self, fn, *args, **kwargs)
    210                 if not self._wrap_exception and attempt.has_exception:
    211                     # get() on an attempt with an exception should cause it to be raised, but raise just in case
--> 212                     raise attempt.get()
    213                 else:
    214                     raise RetryError(attempt)

/opt/anaconda3/lib/python3.7/site-packages/retrying.py in get(self, wrap_exception)
    245                 raise RetryError(self)
    246             else:
--> 247                 six.reraise(self.value[0], self.value[1], self.value[2])
    248         else:
    249             return self.value

/opt/anaconda3/lib/python3.7/site-packages/six.py in reraise(tp, value, tb)
    701             if value.__traceback__ is not tb:
    702                 raise value.with_traceback(tb)
--> 703             raise value
    704         finally:
    705             value = None

/opt/anaconda3/lib/python3.7/site-packages/retrying.py in call(self, fn, *args, **kwargs)
    198         while True:
    199             try:
--> 200                 attempt = Attempt(fn(*args, **kwargs), attempt_number, False)
    201             except:
    202                 tb = sys.exc_info()

/opt/anaconda3/lib/python3.7/site-packages/jupyter_dash/jupyter_app.py in wait_for_app()
    313                     "Address '{url}' already in use.\n"
    314                     "    Try passing a different port to run_server.".format(
--> 315                         url=url
    316                     )
    317                 )

OSError: Address 'http://127.0.0.1:2000' already in use.
    Try passing a different port to run_server.

[nijatullahmansoor]

app.run_server(mode=“inline”, host=“localhost”,port=8051)

so just pass different parameter port=? port number which is valid and not used I tried this it work for me OSError: Address ‘http://127.0.0.1:8050’ already in use. Try passing a different port to run_server.

[brentkendrick]

The port busy error can also arise when you have two or more layout components that have the same id assigned. Usually the traceback will indicate a “DuplicateIdError” as well, but if you are importing layouts (e.g. from other python files) the only error that you might see is the “Address … already in use” error.