I cant start my curseforge mod (Rebirth Of The Night)

I was trying to follow this steps in order to make my server work:

  1. download the server files to your desktop.
  2. open the webui and log in as your normal user (not root)
  3. Import the server through the “import a server” functionality on the left.
  4. Using a terminal session, log in as the same normal user
  5. Navigate to /var/games/minecraft/servers/[servername] .
  6. skip right through to the actual line: java -jar forge-1.12.2- --installServer
  7. From the webui, accept the eula and start the server.
    But in the end, when I try to start my server nothing happens!! I am in a Linux OS. (The last version of Ubuntu). When I try to start a vanilla server it works perfectly. The problem is with the mods server!

This is what appears in my mineOS.log:

{“command”:“start”,“uuid”:“81522540-dce4-11ea-b282-2ba4eb9aa06b”,“time_initiated”:1597268456852,“success”:false,“err”:"!up",“time_resolved”:1597268457012,“level”:“error”,“message”:"[RebrithOfTheNight] command “start” errored out:",“timestamp”:“2020-08-12T21:40:57.013Z”}
{“level”:“info”,“message”:"[RebrithOfTheNight] issued command : “modify_sc”",“timestamp”:“2020-08-12T21:41:02.430Z”}
{“level”:“info”,“message”:"[RebrithOfTheNight] received request “modify_sc”",“timestamp”:“2020-08-12T21:41:02.431Z”}
{“level”:“info”,“message”:"[RebrithOfTheNight] issued command : “start”",“timestamp”:“2020-08-12T21:41:03.696Z”}
{“level”:“info”,“message”:"[RebrithOfTheNight] received request “start”",“timestamp”:“2020-08-12T21:41:03.696Z”}