Elastic-agent log errors

Hello! some time ago i discovered some strange logs that elastic agent throws. it writes it into

.ds-logs-elastic_agent.fleet_server-default

index and this path on host

/opt/Elastic/Agent/data/elastic-agent-8.15.3-619758/logs/elastic-agent-20241108-67.ndjson

next is one of logs, they appear every minute

{"log.level":"error","@timestamp":"2024-11-08T11:17:25.212Z","message":"failed to fetch elasticsearch version","component":{"binary":"fleet-server","dataset":"elastic_agent.fleet_server","id":"fleet-server-default","type":"fleet-server"},"log":{"source":"fleet-server-default"},"service.name":"fleet-server","service.type":"fleet-server","error.message":"elastic fail 401: security_exception: missing authentication credentials for REST request [/]","ecs.version":"1.6.0","ecs.version":"1.6.0"}

agent has a fleet server & heartbeat policy at the same time and also it is ok and send all needed information to cluster, that i can see in dashboards
please help me find where the problem is