Verify that the data input points to that index and is enable.
Verify that the port can be open by splunk user, its mean that if splunk is running with not root user, all ports under 1024 are forbiden.
Verify with telnet from the server that you can open a connection localyt to that port.
Hope i help you
The Data Inputs has been configured for UDP port 1514
Source Type = a10 (chosen from List)
More settings : Set host = IP / Index = a10networks / Restrict to Host = 'empty'
Props.conf (under default) has been updated for port 1514
udp 0 0 xxx.xxx.xxx.xxx:1514 0.0.0.0:*
As it's an UDP port, telnet propably doens't work ...