/saves/server-settings.json file.
Click "Edit Server Config"
Fid the line that looks like this.
"_comment_credentials": "Your factorio.com login credentials. Required for games with visibility public",
"username": "ADF-Sniper",
"password": "mysecretpassword",
"_comment_token": "Authentication token. May be used instead of password above.",
"token": "",
or
"_comment_credentials": "Your factorio.com login credentials. Required for games with visibility public",
"username": "ADF-Sniper",
"password": "",
"_comment_token": "Authentication token. May be used instead of password above.",
"token": "YOURTOKEN",
now start your server.