使用 Flask 报错

from flask import Flask
app = Flask(__name__)

@app.route("/")
def hello():
    return "1234"
if __name__=="__main__":
    app.run()

Traceback (most recent call last):
  File "<input>",line 1,in <module>
  File "D:pythoninstallhelperspydev_pydev_bundlepydev_umd.py",line 197,in runfile
    pydev_imports.execfile(filename,global_vars,local_vars)  # execute the script
  File "D:pythoninstallhelperspydev_pydev_imps_pydev_execfile.py",line 18,in execfile
    exec(compile(contents+"n",file,‘exec‘),glob,loc)
  File "E:/Python/UseTest.py",line 8,in <module>
    app.run()
  File "C:UsersyouzikuAppDataRoamingPythonPython36site-packagesflaskapp.py",line 990,in run
    run_simple(host,port,self,**options)
  File "C:UsersyouzikuAppDataRoamingPythonPython36site-packageswerkzeugserving.py",line 1009,in run_simple
    inner()
  File "C:UsersyouzikuAppDataRoamingPythonPython36site-packageswerkzeugserving.py",line 962,in inner
    fd=fd,File "C:UsersyouzikuAppDataRoamingPythonPython36site-packageswerkzeugserving.py",line 805,in make_server
    host,app,request_handler,passthrough_errors,ssl_context,fd=fd
  File "C:UsersyouzikuAppDataRoamingPythonPython36site-packageswerkzeugserving.py",line 698,in __init__
    HTTPServer.__init__(self,server_address,handler)
  File "C:Program Files (x86)Microsoft Visual StudioSharedPython36_64libsocketserver.py",line 453,in __init__
    self.server_bind()
  File "C:Program Files (x86)Microsoft Visual StudioSharedPython36_64libhttpserver.py",line 138,in server_bind
    self.server_name = socket.getfqdn(host)
  File "C:Program Files (x86)Microsoft Visual StudioSharedPython36_64libsocket.py",line 673,in getfqdn
    hostname,aliases,ipaddrs = gethostbyaddr(name)
UnicodeDecodeError: ‘utf-8‘ codec can‘t decode byte 0xb3 in position 8: invalid start byte

if __name__ == ‘__main__‘:
    app.run(host="0.0.0.0",debug=True,port=9999)