Mender-client 3.5.2 receive "503 Service Unavailable" on update-check [Sync]

General Discussions
1

Hi!

The mender-client on our devices receive “503” from time to time when doing the periodic update checks.

What could be the issue?

Thanks!

level=info msg="State transition: check-wait [Idle] -> update-check [Sync]"
level=error msg="Post \"https://hosted.mender.io/api/devices/v2/deployments/device/deployments/next\": EOF" thread=proxy
level=error msg="Error receiving scheduled update data: failed to check update info on the server. Response: &{503 Service Unavailable 503 HTTP/1.1 1 1 map[Content-Length:[88] Content-Type:[text/plain; charset=utf-8] Date:[Tue, 23 Apr 2024 20:11:40 GMT] X-Content-Type-Options:[nosniff]] 0x121c0f0 88 [] false false map[] 0x1204200 <nil>}"
level=error msg="Update check failed: transient error: failed to check update info on the server. Response: &{503 Service Unavailable 503 HTTP/1.1 1 1 map[Content-Length:[88] Content-Type:[text/plain; charset=utf-8] Date:[Tue, 23 Apr 2024 20:11:40 GMT] X-Content-Type-Options:[nosniff]] 0x121c0f0 88 [] false false map[] 0x1204200 <nil>}"
level=info msg="State transition: update-check [Sync] -> error [Error]"
level=info msg="Handling error state, current error: transient error: failed to check update info on the server. Response: &{503 Service Unavailable 503 HTTP/1.1 1 1 map[Content-Length:[88] Content-Type:[text/plain; charset=utf-8] Date:[Tue, 23 Apr 2024 20:11:40 GMT] X-Content-Type-Options:[nosniff]] 0x121c0f0 88 [] false false map[] 0x1204200 <nil>}"
level=info msg="State transition: error [Error] -> idle [Idle]"
level=info msg="State transition: idle [Idle] -> check-wait [Idle]"
2

This is happening more frequently since a couple of weeks ago. Retrying update-check solves it after a few attempts.

Recent changes at hosted mender that introduced this?