server loads, starts and then apparently goes offline

Hello, I have a problem with my server.
My friend and I wanted to play FTB Space Astronomy (the lastest version is 1.7.3) on a private server, so we decided to use Aternos.
At the beginning the server was running well, but three weeks ago it began having issues: when it is about to go online (the last steps before it says "ONLINE"), it suddenly stops and apparently returns offline!
I said "apparently" because sometimes, after a bunch of minutes, it automatically says "STARTING..." again, and then it goes back to "OFFLINE"!!! I'm getting crazy!
I'm sure that the world isn't corrupted, because in the last days I tested it in a server hosted on my PC, and I didn't notice any problem or corruption (except for a shared offset chunk and some wrong-located entities, but I fixed them).
Here are the last steps before the server stops (I couldn't get the entire log, because in the last steps the server clears the log page)

https://mclo.gs/9ZxwGJj

[18:07:41] [Server thread/INFO]: Starting minecraft server version 1.7.10
2[18:11:46] [Server thread/INFO]: Loading properties
3[18:11:46] [Server thread/INFO]: Default game type: SURVIVAL
4[18:11:46] [Server thread/INFO]: Generating keypair
5[18:11:46] [Server thread/INFO]: Starting Minecraft server on *:48009

Any help would be VERY appreciated. Thanks in advance

I reinstalled the server multiple times, but nothing changed. I don't know if it's a problem of my account...
Should I try the world in my friend's account?

Well, I tried deleting my account and creating a new one, but it hasn't solved the problem. The only problem it could be, I think, is my world.
May it be an overloaded server? How can I manage to run it on aternos?
Host the server on my computer is a pain, because the game and the server take almost all my memory (8 GB)