Epol_ctll() returned with an unexpected error code
This is a problem that usually should not occur. It happens, when the epoll_ctl API fails. One probable cause is that rsyslog was build on a newer kernel than the running kernel. If this is the cause, a correction is available in 5.7.10 and above. If you see this error under other circumstances, please post a description of your environment and what you see to the attached discussion thread. We would really love to sort out reasons if this problem still exists.