This looks like a very unstable network connection. How are your Raspberrymatic and OH server connected to your network? WiFi or Ethernet cable?
The problem could also be caused on the OH side: either the necessary ports on your OH server are not open or you have to explicitly configure the “Callback Network Address” in the bridge configuration. This is necessary if the OH server has more than one IP address or is running e.g. in a docker container.
What kind of Raspi are you using for the CCU?
BTW: I am missing the information about the used server machine and OS. Without these information I can only try to guess.
Connection lost on gateway ‘70194fa126’, cause: “No Pong received!”