Basically I could connect to my server if it was online mode.
If i connect to my server with offline mode.I can’t and the console spamming this error
--------> Spamming error - Pastebin
I’m using up-to-date sponge/forge/mods.
Forge 1.12.2-2854
Spongeforge 7.3.0
How much memory are you allocating to it?
Are you running it as an administrator, or as a regular user, and in what OS.
You can also try toggling the use-native-transport option in the server.properties file while the server is stopped, and see if that helps.
If that doesn’t help, along with the above asked questions, getting a full debug.log file would probably help more.