AWS SES and Bounce email

We have currently set up AWS SES with both DKIM and MAIL FROM. Both enabled and DNS validated through Route53. We set up the SNS topic for receiving Bounce and Complaints.

Anyways we are receiving a lot of Bounce from our customers. The error code that we are receiving is:

        "action": "failed",
        "status": "5.2.0",
        "diagnosticCode": "smtp; 550 5.2.0 Q3PDn2BNoH1DiQ3PEnbLVQ  invalid domain"

We have confirmed that recipient email are valid but still we are receiving this bounce error. How can I diagnosis this situation? How can I prevent from happening?

PS: We are not reaching quota limit and our bounce rate is healthy. Am I missing some SES configuration ? or is it the SES service that is blocking sending email? Thanks and best regards