Sudden mqtt problem

All of a sudden I get these errors when I start HA:

2017-08-27 14:11:13 ERROR (MainThread) [homeassistant.setup] Error during setup of component mqtt
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/homeassistant/setup.py", line 191, in _async_setup_component
    result = yield from component.async_setup(hass, processed_config)
  File "/usr/lib/python3.6/site-packages/homeassistant/components/mqtt/__init__.py", line 387, in async_setup
    success = yield from hass.data[DATA_MQTT].async_connect()
  File "/usr/lib/python3.6/site-packages/homeassistant/components/mqtt/__init__.py", line 497, in async_connect
    self._mqttc.connect, self.broker, self.port, self.keepalive)
  File "/usr/lib/python3.6/asyncio/futures.py", line 331, in __iter__
    yield self  # This tells Task to wait for completion.
  File "/usr/lib/python3.6/asyncio/tasks.py", line 244, in _wakeup
    future.result()
  File "/usr/lib/python3.6/asyncio/futures.py", line 244, in result
    raise self._exception
  File "/usr/lib/python3.6/concurrent/futures/thread.py", line 55, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/lib/python3.6/site-packages/paho/mqtt/client.py", line 760, in connect
    return self.reconnect()
  File "/usr/lib/python3.6/site-packages/paho/mqtt/client.py", line 919, in reconnect
    sock.do_handshake()
  File "/usr/lib/python3.6/ssl.py", line 1061, in do_handshake
    self._sslobj.do_handshake()
  File "/usr/lib/python3.6/ssl.py", line 683, in do_handshake
    self._sslobj.do_handshake()
ssl.SSLEOFError: EOF occurred in violation of protocol (_ssl.c:749)

2017-08-27 14:11:22 ERROR (MainThread) [homeassistant.setup] Unable to setup dependencies of device_tracker.owntracks. Setup failed for dependencies: mqtt

I have not changed anything, and Zanzito connects fine on the phone.

mqtt:
  broker: xx.cloudmqtt.com
  port: 27297
  username:
  password:

In cloudmqtt’s log, I see a lot of these however:

1503834564: Client connection from xxx.xxx.xx.xx denied access by tcpd.

What’s the problem here? Is it on cloudmqtt’s end?

Edit:
After a few restarts of cloudmqtt’s mosquitto, the problem went away.
Hopefully it’s solved now.