share rejected (Upstream not connected)

[grizscom]

I have proxied stratum-connection from miner via my vps (Ubuntu 12.04 x64) to some stratum server.

everything works fine up to a point (not systematic): there is a miner: Rejected (Upstream not connected).
Debug logs proxy's:
DEBUG protocol protocol.lineReceived # > {u'error': None, u'id': 1, u'result': [[[u'mining.set_difficulty', u'ddbeefcafebabe2d35040000000000'], [u'mining.notify', u'ddbeefcafebabe2d35040000000000']], u'07fc2acc', 4]}
DEBUG protocol protocol.lineReceived # > {u'params': [20], u'id': None, u'method': u'mining.set_difficulty'}
INFO proxy client_service.handle_event # Setting new difficulty: 20
DEBUG protocol protocol.lineReceived # > {u'params': [u'7e5', u'rfvnmvjibnfvl3ba7bb', u'01000000010000000000000000000000000000000000000000000000000000000000000000ffffffff2703010308062f503253482f0485dca55408', u'rfvnmvjibnfvl3ba7bb756d2f0000000001004e0fea6b0100001976a9146ef56b7efcadea94b8915ab3f0a727abe85529e688ac00000000', [u'rfvnmvjibnfvl3ba7bbd802a018a97ffe3212c61bfccb65ceb0cef1', u'rfvnmvjibnfvl3ba7bb093d832283231f9acd9ec8062232b48ada0a0752a1118', u'26656cerfvnmvjibnfvl3ba7bbb6b5b3c7cb0838bc6978910389f4df78f3c23'], u'00620002', u'1b0280e1', u'54a5dc85', True], u'id': None, u'method': u'mining.notify'}
INFO proxy client_service.handle_event # New job 7e5 for prevhash 25d387c9, clean_jobs=True
DEBUG protocol protocol.lineReceived # > {u'error': [21, u'job not found'], u'id': 2, u'result': None}
WARNING protocol protocol.dataReceived # Failed message: list index out of range from XX.XX.XX.XX
INFO proxy mining_proxy.on_disconnect # Disconnected from Stratum pool at XX.XX.XX.XX:3333
INFO stats stats.print_stats # 3 peers connected, state changed 1 times
Unhandled error in Deferred:
Unhandled Error
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/Twisted-13.2.0-py2.7-linux-x86_64.egg/twisted/internet/tcp.py", line 299, in connectionLost
protocol.connectionLost(reason)
File "/usr/local/lib/python2.7/dist-packages/stratum-0.2.15-py2.7.egg/stratum/protocol.py", line 329, in connectionLost
d.callback(self.factory)
File "/usr/local/lib/python2.7/dist-packages/Twisted-13.2.0-py2.7-linux-x86_64.egg/twisted/internet/defer.py", line 382, in callback
self._startRunCallbacks(result)
File "/usr/local/lib/python2.7/dist-packages/Twisted-13.2.0-py2.7-linux-x86_64.egg/twisted/internet/defer.py", line 490, in _startRunCallbacks
self._runCallbacks()
--- ---
File "/usr/local/lib/python2.7/dist-packages/Twisted-13.2.0-py2.7-linux-x86_64.egg/twisted/internet/defer.py", line 577, in _runCallbacks
current.result = callback(current.result, _args, *_kw)
File "/home/grizscom/stratum-mining-proxy/mining_proxy.py", line 118, in on_disconnect
stratum_listener.MiningSubscription.disconnect_all()
File "/home/grizscom/stratum-mining-proxy/mining_libs/stratum_listener.py", line 52, in disconnect_all
if subs.connection_ref().transport != None:
exceptions.AttributeError: 'NoneType' object has no attribute 'transport'
DEBUG socket_transport socket_transport.clientConnectionLost # [Failure instance: Traceback (failure with no frames): <class 'twisted.internet.error.ConnectionLost'>: Connection to the other side was lost in a non-clean fashion.

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