You sent more than one identify payload. Don't do that!
The account token sent with your identify payload is incorrect
You sent an invalid payload to us. Don't do that!
You sent a disallowed intent for a Gateway Intent. You may have tried to specify an intent that you have not enabled or are not whitelisted for
You sent an invalid version for the gateway
You sent an invalid intent for a Gateway Intent. You may have incorrectly calculated the bitwise value
The sequence sent when resuming the session was invalid. Reconnect and start a new session
You sent us an invalid shard when identifying
You sent us a payload prior to identifying
Woah nelly! You're sending payloads to us too quickly. Slow it down! You will be disconnected on receiving this
Your session timed out. Reconnect and start a new one
The session would have handled too many guilds - you are required to shard your connection in order to connect
We're not sure what went wrong. Try reconnecting?
You sent an invalid Gateway opcode or an invalid payload for an opcode. Don't do that!
See
https://discord.com/developers/docs/topics/opcodes-and-status-codes#gateway-gateway-close-event-codes