After installing, Elastic Agents it keeps in "Offline" state and "Healthy" intermittently. When checking Agent logs I found this error several times:
[elastic_agent][error] Could not communicate with fleet-server Checking API will retry, error: status code: 429, fleet-server returned an error: MaxLimit, message: exceeded the max limit
Please note that I have APM-Fleet server in Elastic cloud with 1GB RAM (2 zones). Attached you'll find a screenshot where you can see I don't even have 1,000 agents installed.