MQTT client looses connection to the Broker

[NitramLegov]

Unfortunately, the MQTT client looses the connection to the broker regularly.

In the broker log, you can see that the client tries to reconnect, but the broker throws an socket error.
We have two options:

1. change the mqtt library used on the client side (@Narquadah mentioned pubsubclient works for him).
   Here we need to ensure the paket sizes can be adjusted. According to Function to change the MQTT packet size outside of the library knolleary/pubsubclient#110 this should work.
2. Try to debug why there is a socket error.