Sophos UTM 9.5: Webserver Protection slotmem_create failed

4 days after I upgraded one customer, they started complaining about not being able to reach their websites.

Looking into Webserver Protection, all webservers had an yellow exclamation mark on the, and when mouse held over it showed “internal error”, the log showed this:

2017:05:17-00:03:06 fw01 reverseproxy: [Wed May 17 00:03:06.000810 2017] [proxy_protocol:notice] [pid 21492:tid 4152121024] ProxyProtocol: disabled on 127.0.0.1:4080
2017:05:17-00:03:06 fw01 reverseproxy: [Wed May 17 00:03:06.001023 2017] [security2:notice] [pid 21492:tid 4152121024] ModSecurity for Apache/2.7.4 (http://www.modsecurity.org/) configured.
2017:05:17-00:03:06 fw01 reverseproxy: [Wed May 17 00:03:06.001035 2017] [security2:notice] [pid 21492:tid 4152121024] ModSecurity: APR compiled version=”1.5.1″; loaded version=”1.5.1″
2017:05:17-00:03:06 fw01 reverseproxy: [Wed May 17 00:03:06.001051 2017] [security2:notice] [pid 21492:tid 4152121024] ModSecurity: PCRE compiled version=”7.8 “; loaded version=”7.8 2008-09-05″
2017:05:17-00:03:06 fw01 reverseproxy: [Wed May 17 00:03:06.001060 2017] [security2:notice] [pid 21492:tid 4152121024] ModSecurity: LIBXML compiled version=”2.7.6”
2017:05:17-00:03:06 fw01 reverseproxy: [Wed May 17 00:03:06.207757 2017] [slotmem_shm:error] [pid 21497:tid 4152121024] AH02599: existing shared memory for /var/run/apache2/slotmem-shm-p98831e12.shm could not be used (failed size check)
2017:05:17-00:03:06 fw01 reverseproxy: [Wed May 17 00:03:06.207917 2017] [proxy_balancer:emerg] [pid 21497:tid 4152121024] (22)Invalid argument: AH01179: balancer slotmem_create failed
2017:05:17-00:03:06 fw01 reverseproxy: [Wed May 17 00:03:06.207960 2017] [:emerg] [pid 21497:tid 4152121024] AH00020: Configuration Failed, exiting

And selfmon log showed that reverse proxy was restarting over and over.

This fix was this:

https://community.sophos.com/kb/en-us/121309

Actually one need to SSH into the appliance and do this: