Description of problem:
Apparently, it happens when NetworkManager L2TP plugin issues 'ipsec --restart' to restart ipsec service which is done using systemctl 
SELinux is preventing systemctl from using the 'sys_resource' capabilities.

*****  Plugin sys_resource (91.4 confidence) suggests   **********************

If you do not want processes to require capabilities to use up all the system resources on your system;
Then you need to diagnose why your system is running out of system resources and fix the problem.  

According to /usr/include/linux/capability.h, sys_resource is required to:

/* Override resource limits. Set resource limits. */
/* Override quota limits. */
/* Override reserved space on ext2 filesystem */
/* Modify data journaling mode on ext3 filesystem (uses journaling
   resources) */
/* NOTE: ext2 honors fsuid when checking for resource overrides, so
   you can override using fsuid too */
/* Override size restrictions on IPC message queues */
/* Allow more than 64hz interrupts from the real-time clock */
/* Override max number of consoles on console allocation */
/* Override max number of keymaps */
/* Override resource limits. Set resource limits. */
/* Override quota limits. */
/* Override reserved space on ext2 filesystem */
/* Modify data journaling mode on ext3 filesystem (uses journaling
   resources) */
/* NOTE: ext2 honors fsuid when checking for resource overrides, so
   you can override using fsuid too */
/* Override size restrictions on IPC message queues */
/* Allow more than 64hz interrupts from the real-time clock */
/* Override max number of consoles on console allocation */
/* Override max number of keymaps */
/* Override resource limits. Set resource limits. */
/* Override quota limits. */
/* Override reserved space on ext2 filesystem */
/* Modify data journaling mode on ext3 filesystem (uses journaling
   resources) */
/* NOTE: ext2 honors fsuid when checking for resource overrides, so
   you can override using fsuid too */
/* Override size restrictions on IPC message queues */
/* Allow more than 64hz interrupts from the real-time clock */
/* Override max number of consoles on console allocation */
/* Override max number of keymaps */

Do
fix the cause of the SYS_RESOURCE on your system.

*****  Plugin catchall (9.59 confidence) suggests   **************************

If you believe that systemctl should have the sys_resource capability by default.
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# grep systemctl /var/log/audit/audit.log | audit2allow -M mypol
# semodule -i mypol.pp

Additional Information:
Source Context                system_u:system_r:ipsec_mgmt_t:s0
Target Context                system_u:system_r:ipsec_mgmt_t:s0
Target Objects                Unknown [ capability ]
Source                        systemctl
Source Path                   systemctl
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           
Target RPM Packages           
Policy RPM                    selinux-policy-3.13.1-158.7.fc23.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     (removed)
Platform                      Linux (removed) 4.3.5-300.fc23.x86_64 #1 SMP Mon
                              Feb 1 03:18:41 UTC 2016 x86_64 x86_64
Alert Count                   1
First Seen                    2016-03-02 19:43:59 IRST
Last Seen                     2016-03-02 19:43:59 IRST
Local ID                      2a765ce2-8048-47bf-826f-60d2f2819038

Raw Audit Messages
type=AVC msg=audit(1456935239.479:850): avc:  denied  { sys_resource } for  pid=29543 comm="systemctl" capability=24  scontext=system_u:system_r:ipsec_mgmt_t:s0 tcontext=system_u:system_r:ipsec_mgmt_t:s0 tclass=capability permissive=0


Hash: systemctl,ipsec_mgmt_t,ipsec_mgmt_t,capability,sys_resource

Version-Release number of selected component:
selinux-policy-3.13.1-158.7.fc23.noarch

Additional info:
reporter:       libreport-2.6.4
hashmarkername: setroubleshoot
kernel:         4.3.5-300.fc23.x86_64
type:           libreport

Potential duplicate: bug 1189357