AWS Amplify once per 2 days change CNAME for no reason

Question

Hi
I'm using AWS Amplify to host my web app and a third-party service to handle my DNS (it's Cloudflare in my case). 
I've noticed that for my subdomains apps (test.example.com) on Amplify once per 2 days CNAME changes, and my website doesn't work until I manually update CNAME in Cloudflare.
But for the main domain (example.com) the same setup works without problems.
How to fix it and do not update CNAME for Amplify?

AWS-User-knoxy · Answer

Amplify domain management looks for the CNAME entries for each of your custom domain with the value (CloudFront distribution domain) it has given you, and if they don't match within the timeout period,  it will change the distribution.

Update the CNAME for 'test' in your CloudFlare hosted zone .example.com' with the current value,  making sure the '**Proxy status**' setting for the 'test' name is '**DNS only**'.  Then test to see if it resolves to the correct value using  https://www.whatsmydns.net/ as per [1] below.  If the CNAME is not resolving correctly but you have updated it you will need to troubleshoot why.

[1] How do I verify that my CNAME resolves? - https://docs.aws.amazon.com/amplify/latest/userguide/custom-domain-troubleshoot-guide.html#how-do-i-verify-that-my-cname-resolves

AWS Amplify once per 2 days change CNAME for no reason

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