Hello I noticed in 8.5 04-15 I saw the following message in the log:

2019-05-09 00:02:07 *** Average system pressure in the past 4 days was 17 ***
2019-05-09 04:07:08 System pressure is above allowed level
2019-05-09 04:12:08 System pressure is above allowed level
2019-05-09 04:17:08 System pressure is above allowed level
2019-05-09 04:17:08 System pressure too high, attempting to shutdown server...


after which the server shut itself down. Any idea what causes this and how to prevent it?