Discord has recently made updates to their gateway. It looks like your bot is being affected by it. I recommend you to read their update FAQ. Also, I have moved this to #discord-help.
Try to update your discord library / npm module to verison 12
How to remove discord.js : go into your node_modules file with powershell and type : npm uninstall discord.js --save-dev
Install discord.js V12 : npm i discord.js
Well, then just go to Discord Developer portal, click on your bot’s name under My Applications, under Settings, click Bot, scroll down to the Privileged Gateway Intents section, check if Presence Intent and Sever Members Intent are checked or not. If they are not, check them. If your bot has reached 100 servers then you will need to wait for Discord to a) verify your bot and b) later whitelist it.