Occasionally, the API can stop working for whatever reason. If it was working previously and it stopped working on the same version, it means that either we screwed code up or there’s been a change to the Discord API. You can try asking around in the discord.js channel in the API server. You could also make an issue if one relating to a similar issue doesn’t exist. Please post a stacktrace if there is one, and be as detailed as possible - “the API isn’t working” doesn’t help at all.
If there is already an issue, feel free to comment that you’re also experiencing the same thing. This helps to see how widespread the bug is.
You can try reconnecting before submitting an issue, as sometimes some of the servers may be slightly different.