How can I find out why my client is being throttled when subscribing in mqtt?

I have recently begun to see subscribe requests fail with reason "throttled" in the aws iot logs in cloudwatch.

I'm unsure what is causing this or why and need to find out immediately!

How can I learn what the cause for throttling is so I can quickly resolve it?

On that note it would be nice if AWS returned the specific reason instead of the generic "throttled" in the logs!

Example log:

{
    "timestamp": "2023-08-08 22:43:33.727",
    "logLevel": "ERROR",
    "traceId": "X",
    "accountId": "X",
    "status": "Failure",
    "eventType": "Subscribe",
    "protocol": "MQTT",
    "topicName": "users/X/status",
    "clientId": "<clientId>",
    "principalId": "USER",
    "sourceIp": "X",
    "sourcePort": X,
    "reason": "throttled"
}