This is an indication of insufficient memory for the allocated heap.
Could you run "free -m" on the host where Zeppelin is running? Otherwise, if you have access to Ambari dashboard go to the specific host and in the host metrics look at memory usage. You could export the data by clicking on the save icon. Analyze the memory usage over time. Time is expressed in epoch. If you convert it to a readable date/time you may be able to correlate with the time of failure.