Knife ec2 didn't work. Download error with 503

[shgto]

Chef: 12.0.3
ec2: RHEL 7.9, cURL version: 7.80.0
It didn't work when I launched "knife ec2 server create".
After SSH connection established, enountered an ERROR below.
Chef node configuration stopped because no Chef-Client software downloaded and installed.

503 Service Unavailable: Back-end server is at capacity

This code shows a misconfigration or server down on Opscode Server side.
Please reconsider Server settings. or else any idea to solve this problem?

It worked fine with no error working with the same task on 1st, September 2021.