Filebeat sends packets with 0 leangth

Hi,
I'm sending logs to ELK server using filebeat running in the syslog server. I dont get any update in KIbana. Then I check the packets (using tcpdump) in the syslog server (where filebeat runs), all packets are with 0 length.

Then I check with
Output.console
pretty: true

and observed that file beat reads the log files without any issue.
What is the possible issue? This was worked very fine few days ago!

My filebeat version 7.5.1

Following are the filebeat logs which seems normal to me

2020-01-16T08:27:30.707Z INFO [monitoring] log/log.go:145 Non-zero metrics in the last 30s {"monitoring": {"metrics": {"beat":{"cpu":{"system":{"ticks":420,"time":{"ms":4}},"total":{"ticks":1560,"time":{"ms":10},"value":1560},"user":{"ticks":1140,"time":{"ms":6}}},"handles":{"limit":{"hard":4096,"soft":1024},"open":8},"info":{"ephemeral_id":"ac23bda1-059b-431a-9e4e-7c892be68c6f","uptime":{"ms":1410103}},"memstats":{"gc_next":21941408,"memory_alloc":11657280,"memory_total":49431000},"runtime":{"goroutines":27}},"filebeat":{"harvester":{"open_files":1,"running":1}},"libbeat":{"config":{"module":{"running":0}},"output":{"read":{"bytes":36}},"pipeline":{"clients":1,"events":{"active":4117}}},"registrar":{"states":{"current":1}},"system":{"load":{"1":1.02,"15":0.97,"5":1.01,"norm":{"1":0.1275,"15":0.1213,"5":0.1263}}}}}}
2020-01-16T08:28:00.707Z INFO [monitoring] log/log.go:145 Non-zero metrics in the last 30s {"monitoring": {"metrics": {"beat":{"cpu":{"system":{"ticks":420,"time":{"ms":3}},"total":{"ticks":1570,"time":{"ms":9},"value":1570},"user":{"ticks":1150,"time":{"ms":6}}},"handles":{"limit":{"hard":4096,"soft":1024},"open":8},"info":{"ephemeral_id":"ac23bda1-059b-431a-9e4e-7c892be68c6f","uptime":{"ms":1440104}},"memstats":{"gc_next":21941408,"memory_alloc":12034544,"memory_total":49808264},"runtime":{"goroutines":27}},"filebeat":{"harvester":{"open_files":1,"running":1}},"libbeat":{"config":{"module":{"running":0}},"output":{"read":{"bytes":36}},"pipeline":{"clients":1,"events":{"active":4117}}},"registrar":{"states":{"current":1}},"system":{"load":{"1":1.01,"15":0.97,"5":1.01,"norm":{"1":0.1263,"15":0.1213,"5":0.1263}}}}}}
2020-01-16T08:28:30.707Z INFO [monitoring] log/log.go:145 Non-zero metrics in the last 30s {"monitoring": {"metrics": {"beat":{"cpu":{"system":{"ticks":420,"time":{"ms":3}},"total":{"ticks":1610,"time":{"ms":42},"value":1610},"user":{"ticks":1190,"time":{"ms":39}}},"handles":{"limit":{"hard":4096,"soft":1024},"open":8},"info":{"ephemeral_id":"ac23bda1-059b-431a-9e4e-7c892be68c6f","uptime":{"ms":1470104}},"memstats":{"gc_next":21941120,"memory_alloc":11139208,"memory_total":50092696},"runtime":{"goroutines":27}},"filebeat":{"harvester":{"open_files":1,"running":1}},"libbeat":{"config":{"module":{"running":0}},"output":{"read":{"bytes":36}},"pipeline":{"clients":1,"events":{"active":4117}}},"registrar":{"states":{"current":1}},"system":{"load":{"1":0.95,"15":0.97,"5":0.99,"norm":{"1":0.1188,"15":0.1213,"5":0.1238}}}}}}
Disclaimer :

Thanks in advance!

KR