Friend's server doesn't work on Sky Factory 3

So this morning my friend was starting up his Sky Factory 3 server and when I went into the server list it said that client was outdated and that the server was a vanilla server. A few minutes after that he said his server crashed after a bit of starting. His Aternos user is PersonIGuess the only reason I am making this and not him is because he didn't want to.

No I looked on his server after he said he had given up and it said it was Sky Factory 3's proper version and no it is not. Aternos servers do not like mod packs it seems since people before have said they had this issue.