Previously, access was carried out via tcp/8080 port. But today it was configured to use a tcp/https connection using a self-signed certificate. After these settings, the server was restarted and access was lost.

denis@ubuntu:~$ sudo netstat -ntlp | grep LISTEN

tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      1081/sshd       
tcp        0      0 127.0.0.1:13306         0.0.0.0:*               LISTEN      5635/postgres   
tcp        0      0 127.0.0.1:32000         0.0.0.0:*               LISTEN      5597/java       
tcp6       0      0 :::8080                 :::*                    LISTEN      5597/java       
tcp6       0      0 :::22                   :::*                    LISTEN      1081/sshd       
tcp6       0      0 ::1:13306               :::*                    LISTEN      5635/postgres   
tcp6       0      0 :::34878                :::*                    LISTEN      5597/java       
tcp6       0      0 :::43970                :::*                    LISTEN      5597/java