If you are asking about a problem you are experiencing, please use the following template, as it will help us help you. If you have a different problem, please delete all of this text 
APM Agent get Queue when APM server is unavailable for a longer period of time.
Kibana version: kibana-7.3.0-linux-x86_64
Elasticsearch version:elasticsearch-7.3.0-linux-x86_64
APM Server version:apm-server-7.2.1-linux-x86_64
APM Agent language and version:
Original install method (e.g. download page, yum, deb, from source, etc.) and version:
from source
Fresh install or upgraded from other version?
fresh install
Is there anything special in your setup? For example, are you using the Logstash or Kafka outputs? Are you using a load balancer in front of the APM Servers? Have you changed index pattern, generated custom templates, changed agent configuration etc.
NO
Description of the problem including expected versus actual behavior. Please include screenshots (if relevant):
Getting 503 and Queue is full from APM Agent to Apm Server.
Provide logs and/or server output (if relevant):
i2019-08-19T06:07:34.304+0530 ERROR [request] beater/intake_handler.go:94 error handling request {"request_id": "8f8efcf1-e922-48ba-bc88-197664fdf02d", "method": "POST", "URL": "/intake/v2/events", "content_length": -1, "remote_address": "IP", "user-agent": "elasticapm-java/1.8.0", "error": "queue is full", "response_code": 503}
t2019-08-19T06:07:34.725+0530 ERROR [request] beater/intake_handler.go:94 error handling request {"request_id": "da53f684-6198-43f8-bad7-0237c330de08", "method": "POST", "URL": "/intake/v2/events", "content_length": -1, "remote_address": "IP", "user-agent": "elasticapm-java/1.8.0", "error": "queue is full", "response_code": 503}