Looks like you have three problems here.
One is your instance apparently falling off the network which coincides with the Telegram errors:
2018-04-25 12:44:31,786 - octoprint.util.connectivity_checker - INFO - Connectivity changed from online to offline
There's also a myriad of capture errors from the webcam, indicating something's up there as well - that's probably not network related though since it's failing at capturing from the Pi itself (127.0.0.1) and failing, so network connectivity shouldn't be causing trouble there:
2018-04-25 11:12:24,669 - octoprint.timelapse - ERROR - Could not capture image /home/pi/.octoprint/timelapse/tmp/loubie_adalinda_dragon_20180425011537-3140.jpg from http://127.0.0.1:8080/?action=snapshot
Traceback (most recent call last):
File "/home/pi/oprint/local/lib/python2.7/site-packages/octoprint/timelapse.py", line 586, in _perform_capture
File "/home/pi/oprint/local/lib/python2.7/site-packages/requests-2.18.4-py2.7.egg/requests/api.py", line 72, in get
return request('get', url, params=params, **kwargs)
File "/home/pi/oprint/local/lib/python2.7/site-packages/requests-2.18.4-py2.7.egg/requests/api.py", line 58, in request
return session.request(method=method, url=url, **kwargs)
File "/home/pi/oprint/local/lib/python2.7/site-packages/requests-2.18.4-py2.7.egg/requests/sessions.py", line 508, in request
resp = self.send(prep, **send_kwargs)
File "/home/pi/oprint/local/lib/python2.7/site-packages/requests-2.18.4-py2.7.egg/requests/sessions.py", line 618, in send
r = adapter.send(request, **kwargs)
File "/home/pi/oprint/local/lib/python2.7/site-packages/requests-2.18.4-py2.7.egg/requests/adapters.py", line 490, in send
raise ConnectionError(err, request=request)
ConnectionError: ('Connection aborted.', BadStatusLine("''",))
The final issue is that your printer stopped responding to OctoPrint, so after trying to tickle it back into replying for a bit, OctoPrint gave up:
2018-04-25 14:28:03,189 - octoprint.util.comm - INFO - Communication timeout while printing, trying to trigger response from printer.
2018-04-25 14:28:06,468 - octoprint.util.comm - INFO - Communication timeout while printing, trying to trigger response from printer.
2018-04-25 14:28:10,476 - octoprint.util.comm - INFO - Communication timeout while printing, trying to trigger response from printer.
2018-04-25 14:28:14,428 - octoprint.util.comm - INFO - No response from printer after 6 consecutive communication timeouts, considering it dead.
2018-04-25 14:28:15,259 - octoprint.util.comm - INFO - Changing monitoring state from "Printing" to "Offline (Error: Too many consecutive timeouts, printer still connected and alive?)"
To diagnose the last issue further, you'd need to enable
serial.log and try to reproduce this problem.
The first is more tricky to figure out. Could be bad reception, could be power issues, could be your network acting up etc.
/var/log/syslog might contain something helpful there. The second is something I've never before seen but...
All of those issues could be caused by the Pi browning out, so check that your power supply is a) actually a power supply (and not just a cellphone or tablet charger) and b) is actually putting out stable 5V at 2-3A. You wouldn't believe how many strange errors are caused by inadequate power supplies or power wiring.