What is the problem?
The printing stops midway. This happens intermittently.
What did you already try to solve it?
Read here, searched 
Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, octoprint.log, serial.log or output on terminal tab, ...)
octoprint.log:
2019-04-11 15:32:59,919 - octoprint.util.comm - INFO - Communication timeout while idle, trying to trigger response from printer.
2019-04-11 15:36:02,658 - octoprint.util.comm - INFO - Changing monitoring state from "Operational" to "Printing"
2019-04-11 15:36:02,700 - octoprint.util.comm - INFO - M110 detected, setting current line number to 0
2019-04-11 15:37:25,264 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 15:39:51,996 - octoprint.util.comm - INFO - Changing monitoring state from "Printing" to "Pausing"
2019-04-11 15:39:52,482 - octoprint.util.comm - INFO - Changing monitoring state from "Pausing" to "Paused"
2019-04-11 15:39:55,643 - octoprint.util.comm - INFO - Changing monitoring state from "Paused" to "Cancelling"
2019-04-11 15:39:55,808 - octoprint.util.comm - INFO - Changing monitoring state from "Cancelling" to "Operational"
2019-04-11 15:41:39,291 - octoprint.filemanager.analysis - INFO - Starting analysis of local:CE3_Sealant_Cardridge_Cap_V3.gcode
2019-04-11 15:41:39,294 - octoprint.filemanager.analysis - INFO - Invoking analysis command: /home/pi/oprint/bin/python2 -m octoprint analysis gcode --speed-x=6000 --speed-y=6000 --max-t=10 --throttle=0.0 --throttle-lines=100 /home/pi/.octoprint/uploads/CE3_Sealant_Cardridge_Cap_V3.gcode
2019-04-11 15:41:46,494 - octoprint.filemanager.analysis - INFO - Analysis of entry local:CE3_Sealant_Cardridge_Cap_V3.gcode finished, needed 7.20s
2019-04-11 15:42:27,226 - octoprint.util.comm - INFO - Changing monitoring state from "Operational" to "Printing"
2019-04-11 15:42:27,292 - octoprint.util.comm - INFO - M110 detected, setting current line number to 0
2019-04-11 15:48:13,084 - octoprint.util.comm - INFO - Changing monitoring state from "Printing" to "Cancelling"
2019-04-11 15:48:13,324 - octoprint.util.comm - INFO - Changing monitoring state from "Cancelling" to "Operational"
2019-04-11 15:49:57,959 - octoprint.filemanager.analysis - INFO - Starting analysis of local:CE3_Sealant_Cardridge_Cap_V3.gcode
2019-04-11 15:49:57,963 - octoprint.filemanager.analysis - INFO - Invoking analysis command: /home/pi/oprint/bin/python2 -m octoprint analysis gcode --speed-x=6000 --speed-y=6000 --max-t=10 --throttle=0.0 --throttle-lines=100 /home/pi/.octoprint/uploads/CE3_Sealant_Cardridge_Cap_V3.gcode
2019-04-11 15:50:05,308 - octoprint.util.comm - INFO - Changing monitoring state from "Operational" to "Printing"
2019-04-11 15:50:05,333 - octoprint.util.comm - INFO - M110 detected, setting current line number to 0
2019-04-11 15:52:25,267 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 16:07:25,269 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 16:19:25,247 - octoprint.server.util.flask - INFO - Passively logging in user dummy from ::ffff:192.168.1.127
2019-04-11 16:19:27,084 - octoprint.server.util.sockjs - INFO - New connection from client: ::ffff:192.168.1.127
2019-04-11 16:19:27,287 - octoprint.server.util.flask - INFO - Passively logging in user dummy from ::ffff:192.168.1.127
2019-04-11 16:19:29,487 - octoprint.plugins.announcements - INFO - Loaded channel _important from Important OctoPrint Announcements in 0.71s
2019-04-11 16:19:30,653 - octoprint.plugins.announcements - INFO - Loaded channel _releases from OctoPrint Release Announcements in 0.77s
2019-04-11 16:19:31,535 - octoprint.plugins.announcements - INFO - Loaded channel _blog from OctoBlog in 0.78s
2019-04-11 16:19:32,406 - octoprint.plugins.announcements - INFO - Loaded channel _plugins from OctoPrint Plugin Repository in 0.78s
2019-04-11 16:19:33,348 - octoprint.plugins.announcements - INFO - Loaded channel _octopi from OctoPi Announcements in 0.8s
2019-04-11 16:19:53,881 - tornado.access - WARNING - 404 GET /dryrun-activated (::ffff:192.168.1.127) 22.21ms
2019-04-11 16:21:00,273 - octoprint.server.util.sockjs - INFO - New connection from client: ::ffff:192.168.1.127
2019-04-11 16:21:00,450 - octoprint.server.util.flask - INFO - Passively logging in user dummy from ::ffff:192.168.1.127
2019-04-11 16:22:25,272 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 16:28:37,883 - octoprint.util.comm - INFO - Finished in 2312.579 s.
2019-04-11 16:28:37,885 - octoprint.util.comm - INFO - Changing monitoring state from "Printing" to "Finishing"
2019-04-11 16:28:37,895 - octoprint.filemanager.analysis - INFO - Starting analysis of local:CE3_Sealant_Cardridge_Cap_V3.gcode
2019-04-11 16:28:37,903 - octoprint.filemanager.analysis - INFO - Invoking analysis command: /home/pi/oprint/bin/python2 -m octoprint analysis gcode --speed-x=6000 --speed-y=6000 --max-t=10 --throttle=0.0 --throttle-lines=100 /home/pi/.octoprint/uploads/CE3_Sealant_Cardridge_Cap_V3.gcode
2019-04-11 16:28:37,983 - octoprint.util.comm - INFO - Changing monitoring state from "Finishing" to "Operational"
2019-04-11 16:28:50,965 - octoprint.filemanager.analysis - INFO - Analysis of entry local:CE3_Sealant_Cardridge_Cap_V3.gcode finished, needed 13.07s
2019-04-11 16:37:25,275 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 16:44:30,274 - octoprint.filemanager.analysis - INFO - Starting analysis of local:CE3_hotglue_gun_stand_ext.gcode
2019-04-11 16:44:30,276 - octoprint.filemanager.analysis - INFO - Invoking analysis command: /home/pi/oprint/bin/python2 -m octoprint analysis gcode --speed-x=6000 --speed-y=6000 --max-t=10 --throttle=0.0 --throttle-lines=100 /home/pi/.octoprint/uploads/CE3_hotglue_gun_stand_ext.gcode
2019-04-11 16:44:47,593 - octoprint.util.comm - INFO - Changing monitoring state from "Operational" to "Printing"
2019-04-11 16:44:47,619 - octoprint.util.comm - INFO - M110 detected, setting current line number to 0
2019-04-11 16:52:25,278 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 17:07:25,280 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 17:22:25,285 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 17:37:25,287 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 17:41:44,809 - anywhere.mjpeg_stream - ERROR - [Errno 32] Broken pipe
2019-04-11 17:52:25,289 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 18:06:58,002 - octoprint.server.util.sockjs - INFO - Client connection closed: ::ffff:192.168.1.127
2019-04-11 18:06:58,021 - octoprint.server.util.sockjs - INFO - Client connection closed: ::ffff:192.168.1.127
2019-04-11 18:06:58,034 - tornado.application - ERROR - Exception in callback <functools.partial object at 0x6cbacd20>
Traceback (most recent call last):
File "/home/pi/oprint/local/lib/python2.7/site-packages/tornado/ioloop.py", line 605, in _run_callback
ret = callback()
File "/home/pi/oprint/local/lib/python2.7/site-packages/tornado/stack_context.py", line 277, in null_wrapper
return fn(*args, **kwargs)
File "/home/pi/oprint/local/lib/python2.7/site-packages/octoprint/vendor/sockjs/tornado/transports/websocket.py", line 94, in
self.server.io_loop.add_callback(lambda: self.send_pack(message, binary))
File "/home/pi/oprint/local/lib/python2.7/site-packages/octoprint/vendor/sockjs/tornado/transports/websocket.py", line 89, in send_pack
self.write_message(message, binary)
File "/home/pi/oprint/local/lib/python2.7/site-packages/tornado/websocket.py", line 249, in write_message
raise WebSocketClosedError()
WebSocketClosedError
2019-04-11 18:07:25,293 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 18:22:25,295 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 18:37:25,300 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 18:52:25,303 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 19:07:25,306 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 19:22:25,308 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 19:37:25,310 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 19:52:25,312 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 19:59:43,901 - octoprint.server.util.sockjs - INFO - New connection from client: ::ffff:192.168.1.127
2019-04-11 19:59:44,047 - octoprint.server.util.sockjs - INFO - New connection from client: ::ffff:192.168.1.127
2019-04-11 19:59:44,198 - octoprint.server.util.flask - INFO - Passively logging in user dummy from ::ffff:192.168.1.127
2019-04-11 19:59:44,222 - octoprint.server.util.flask - INFO - Passively logging in user dummy from ::ffff:192.168.1.127
2019-04-11 19:59:46,350 - octoprint.server.util.sockjs - INFO - Client connection closed: ::ffff:192.168.1.127
2019-04-11 20:00:06,539 - octoprint.server.util.sockjs - INFO - Client connection closed: ::ffff:192.168.1.127
2019-04-11 20:07:25,315 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 20:22:25,317 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 20:37:25,319 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 20:52:25,321 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 21:07:25,323 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 21:22:25,327 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 21:37:25,331 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 21:52:25,334 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 21:57:26,300 - octoprint.util.comm - INFO - Finished in 18758.708 s.
2019-04-11 21:57:26,303 - octoprint.util.comm - INFO - Changing monitoring state from "Printing" to "Finishing"
2019-04-11 21:57:26,313 - octoprint.filemanager.analysis - INFO - Starting analysis of local:CE3_hotglue_gun_stand_ext.gcode
2019-04-11 21:57:26,330 - octoprint.filemanager.analysis - INFO - Invoking analysis command: /home/pi/oprint/bin/python2 -m octoprint analysis gcode --speed-x=6000 --speed-y=6000 --max-t=10 --throttle=0.0 --throttle-lines=100 /home/pi/.octoprint/uploads/CE3_hotglue_gun_stand_ext.gcode
2019-04-11 21:57:26,484 - octoprint.util.comm - INFO - Changing monitoring state from "Finishing" to "Operational"
2019-04-11 21:58:07,394 - octoprint.filemanager.analysis - INFO - Analysis of entry local:CE3_hotglue_gun_stand_ext.gcode finished, needed 41.08s
2019-04-11 22:07:25,338 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 22:22:25,340 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 22:22:37,012 - octoprint.filemanager.analysis - INFO - Starting analysis of local:CE3_Octopus_v5.5.gcode
2019-04-11 22:22:37,014 - octoprint.filemanager.analysis - INFO - Invoking analysis command: /home/pi/oprint/bin/python2 -m octoprint analysis gcode --speed-x=6000 --speed-y=6000 --max-t=10 --throttle=0.0 --throttle-lines=100 /home/pi/.octoprint/uploads/CE3_Octopus_v5.5.gcode
2019-04-11 22:23:02,335 - octoprint.util.comm - INFO - Changing monitoring state from "Operational" to "Printing"
2019-04-11 22:23:02,366 - octoprint.util.comm - INFO - M110 detected, setting current line number to 0
2019-04-11 22:37:25,344 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 22:48:48,885 - octoprint.util.comm - ERROR - Unexpected error while reading from serial port
Traceback (most recent call last):
File "/home/pi/oprint/local/lib/python2.7/site-packages/octoprint/util/comm.py", line 2605, in _readline
ret = self._serial.readline()
File "/home/pi/oprint/local/lib/python2.7/site-packages/octoprint/util/comm.py", line 4681, in readline
c = self.read(1)
File "/home/pi/oprint/local/lib/python2.7/site-packages/serial/serialposix.py", line 501, in read
'device reports readiness to read but returned no data '
SerialException: device reports readiness to read but returned no data (device disconnected or multiple access on port?)
2019-04-11 22:48:48,889 - octoprint.util.comm - ERROR - Please see https://faq.octoprint.org/serialerror for possible reasons of this.
2019-04-11 22:48:48,913 - octoprint.util.comm - INFO - Changing monitoring state from "Printing" to "Offline (Error: SerialException: 'device reports readiness to read but returned no data (device disconnected or multiple access on port?)' @ comm.py:_readline:2605)"
2019-04-11 22:48:48,949 - octoprint.filemanager.analysis - INFO - Starting analysis of local:CE3_Octopus_v5.5.gcode
2019-04-11 22:48:48,964 - octoprint.filemanager.analysis - INFO - Invoking analysis command: /home/pi/oprint/bin/python2 -m octoprint analysis gcode --speed-x=6000 --speed-y=6000 --max-t=10 --throttle=0.0 --throttle-lines=100 /home/pi/.octoprint/uploads/CE3_Octopus_v5.5.gcode
2019-04-11 22:50:20,629 - octoprint.filemanager.analysis - INFO - Analysis of entry local:CE3_Octopus_v5.5.gcode finished, needed 91.68s
2019-04-11 22:52:25,346 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 23:07:25,349 - octoprint.server.heartbeat - INFO - Server heartbeat <3
2019-04-11 23:22:25,353 - octoprint.server.heartbeat - INFO - Server heartbeat <3