SNMPTrap logstash failed

Hi everyone. I am a beginner of Logstash and try to utilize it to receive the SNMP traps from the managed devices. For convenience, I send the simulated SNMP traps to Logstash server. The problem is I can receive the simulated SNMP when I generate those traps on the same server and send them to the local host But when I try to generate the SNMP traps from other machines like my personal computer(Windows 7), then the Logstash could not receive anything. Can you give some hints about the possible reasons? Thank you very much! Below is the configuration file of my Logstash:

       community => "public"
	   host => ""
       port => 1080

filter {
output {
file {
path => "/home/KH44IM/SNMPTrap.json"

What Logstash version are you using?

Look at Logstash Settings 5.0 to find out how to turn on debug logging.

You should then see a logged message for each trap received - starts with "SNMP Trap received: ...".