HELP, I am not technical, My AWS Certificate Manager (ACM) was unable to renew the certificate automatically using DNS validation. How can I solve this?

There are troubleshooting steps listed here: https://docs.aws.amazon.com/acm/latest/userguide/troubleshooting-renewal.html#troubleshooting-automatic-renewal

Automatic renewal through DNS happens only when you are using R53 to manage your domains. Else you can try email validation Email-validated certificates require an action by the domain owner. ACM begins sending renewal notices 45 days before expiration, using the domain's WHOIS mailbox addresses and to five common administrator addresses. The notifications contain a link that the domain owner can click for easy renewal. Once all listed domains are validated, ACM issues a renewed certificate with the same ARN.

See Validate with Email for instructions on identifying which domains are in the PENDING_VALIDATION state and repeating the validation process for those domains. https://docs.aws.amazon.com/acm/latest/userguide/email-validation.html