Nagios核心服务会经常自动停止

Question

OS – Ubuntu-16.04 LTS
Nagios Core Version – 4.4.3

问题：我们安装了Nagios核心来监视服务器。最近，我们已将操作系统从Ubuntu-14.04 LTS升级到Ubuntu-16.04 LTS，并且我们还将Nagios core升级到了最新版本– 4.4.3。 此更改问题开始后，例如Nagios核心服务自动停止，因此，请在每次需要重新引导系统并手动启动服务时解决此问题。从/usr/local/nagios/var/Nagios.log看到以下消息，我没有看到任何错误。

[1560226379] wproc: NOTIFY job 2530 from worker Core Worker 2214 is a non-check helper but exited with return code 36
[1560226379] wproc:   host=NAGIOS; service=apache2; contact=ajitkumar
[1560226379] wproc:   early_timeout=0; exited_ok=1; wait_status=9216; error_code=0;
[1560226379] wproc:   stderr line 01: mail: cannot send message: Process exited with a non-zero status
[1560226379] wproc:   stderr line 02: mail: Cannot open file /home/nagios/dead.letter: No such file or directory