APM Server response codes
Elastic Stack Serverless Observability
The most likely cause for this error is using incompatible versions of APM agent and APM Server. See the agent/server compatibility matrix to verify compatibility.
The most likely cause for this error is using an incompatible version of an APM agent. See minimum supported APM agent versions to verify compatibility.
APM agents communicate with the APM server by sending events in an HTTP request. Each event is sent as its own line in the HTTP request body. If events are too large, you should consider increasing the Max event size setting in the APM integration, and adjusting relevant settings in the agent.
APM agents communicate with the Managed intake service by sending events in an HTTP request. Each event is sent as its own line in the HTTP request body. If events are too large, you can reduce the size of the events that your APM agents send by: enabling span compression or reducing collected stack trace information.
Either the Secret token in the request header doesn’t match the secret token configured in the APM integration, or the API keys is invalid.
The API key is invalid.
Either you are sending requests to a RUM endpoint without RUM enabled, or a request is coming from an origin not specified in the APM integration settings. See the Allowed origins setting for more information.
This happens when APM Server exceeds the maximum number of requests that it can process concurrently. To alleviate this problem, you can try to: reduce the sample rate and/or reduce the collected stack trace information. See Reduce storage for more information.
Another option is to increase processing power. This can be done by either migrating your Elastic Agent to a more powerful machine or adding more APM Server instances.