Syslog-ng-wec no communication between host and collector

Recently I've installed Syslog-NG PE.
I need to forward events from Windows Servers to WEC.
I have carefully followed all steps from administration guide.
At the beginning the connection was established (Windows 10 -> CentOS 7 with WEC), but in the same time it was closed. Logs below:

2020-09-23T11:23:50.992+0200 DEBUG Connection closed {"address": ""}
2020-09-23T11:30:46.436+0200 DEBUG Connection established {"address": ""}
2020-09-23T11:30:46.546+0200 DEBUG Connection closed {"address": ""}
2020-09-23T11:30:46.608+0200 DEBUG Connection established {"address": ""}
2020-09-23T11:30:46.715+0200 DEBUG Connection closed {"address": ""}
2020-09-23T11:32:03.449+0200 DEBUG Connection established {"address": ""}
2020-09-23T11:32:03.567+0200 DEBUG Connection closed {"address": ""}
2020-09-23T11:32:03.595+0200 DEBUG Connection established {"address": ""}
2020-09-23T11:32:03.713+0200 DEBUG Connection closed {"address": ""}
2020-09-23T11:33:20.447+0200 DEBUG Connection established {"address": ""}
2020-09-23T11:33:20.556+0200 DEBUG Connection closed {"address": ""}
2020-09-23T11:33:20.623+0200 DEBUG Connection established {"address": ""}
2020-09-23T11:33:20.729+0200 DEBUG Connection closed {"address": ""}
2020-09-23T11:34:37.454+0200 DEBUG Connection established {"address": ""}
2020-09-23T11:34:37.554+0200 DEBUG Connection closed {"address": ""}

I thought maybe there were some issues with certificates, so I created a new for a client and for server as well.
After that I did not get any connection back from my host. I have tried with other hosts but the issue was the same.
Can anybody help me somehow to solve this problem?
Thank you in advance.