Steps to reproduce:

1. Create a LLD Item Prototype with thew following Key (Linux only!)

vfs.file.regexp[/proc/mounts," {#FSNAME} {#FSTYPE} (.+) [0-9] [0-9]",,,,\1]

1. Result looks like this:

vfs.file.regexp[/proc/mounts," / ext4 (.+) [0-9] [0-9]",,,,\1]

1. This

zabbix_agent -t 'vfs.file.regexp[/proc/mounts," / ext4 (.+) [0-9] [0-9]",,,,\1]'

is working fine! Result:+
+

vfs.file.regexp[/proc/mounts," / ext4 (.+) [0-9] [0-9]",,,,\1]        [s|rw,relatime,errors=remount-ro,data=ordered]

Result:
But Server is not getting any data?

Also no errors in the Log files (neither Server nor Agent)

Expected:

1. $ zabbix_agentd -t 'vfs.file.regexp[/proc/mounts," / ext4 (.+) [0-9] [0-9]",,,,\1]'
   vfs.file.regexp[/proc/mounts," / ext4 (.+) [0-9] [0-9]",,,,\1] [s|rw,relatime,errors=remount-ro,data=ordered]

1. $ perl -n -e'/ \/ ext4 (.+) [0-9] [0-9]/ && print $1' /proc/mounts
   rw,relatime,errors=remount-ro,data=ordered

So The agent is allowed to read /proc/mounts, and the Reguilar expression is working as expected /testet with zabbix_agent -t and perl. 

I have no Idea why the output is just empty?