Setting freelan to create a minecraft server

Question

I tried to make a minecraft server using server client from minecraft.net and freelan as a hamachi replacement. However, it didn't work. Firstly, I installed freelan on two computers. Then I followed this https://freelan.org/get_help.html#client-certificate-generation . I created certificate authority+key and user certificate+key on first pc using openvpn. After that, I edited freelan.cfg .

Here is my configuration

[tap_adapter]

server_ipv4_address_prefix_length=IPofMyServer/24



[security]

signature_certificate_file=//home/user/.freelan/user.crt
signature_private_key_file=//home/user/.freelan/user.key
authority_certificate_file=//home/user/.freelan/ca.crt

Running freelan from terminal on ubuntu (I use ubuntu on first pc, lubuntu on second) notified me that those files were loaded.

Then I signed user1.crt + user1.key on lubuntu using ca.crt and ca.key from first computer. It succeeded. Here is freelan.cfg on this pc

[fscp]
contact=IPofMyServer

[security]

signature_certificate_file=//home/user/.freelan/user1.crt
signature_private_key_file=//home/user/.freelan/user1.key
authority_certificate_file=//home/user/.freelan/ca.crt

I ran sudo service freelan start on both computers, server client on ubuntu computer and tried to connect to it on lubuntu by typing in minecraft IPofMyServer:[port from server.properties]

Minecraft couldn't see server and displayed [No connection].

What can be wrong there?