ACM: Renewal Status is pending validation even after correct DNS Configuration

Hello.

If you receive that message, it may work if you delete the ACM verification DNS record and then register it again.
https://repost.aws/knowledge-center/certificate-fails-to-auto-renew

Validate that your CNAME validation record is resolvable by using a tool like dig or nslookup or similar to resolve it. A correctly working CNAME should be resolvable as follows from any computer on the Internet. In this case, I am looking up the CNAME _e5f000fdaea220228e420f2b5256e43f.example.com. (Note, this is a fictitious example, you need to use your own CNAME here).

% dig _e5f000fdaea220228e420f2b5256e43f.example.com.

; <<>> DiG 9.10.6 <<>> _e5f000fdaea220228e420f2b5256xxx.swyd.ca.
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11832
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;_e5f000fdaea220228e420f2b5256xxx.example.com. IN A

;; ANSWER SECTION:
_e5f000fdaea220228e420f2b5256xxx.swyd.ca. 300 IN CNAME _aba7aefb0cab414f85c552723a7dxxx.gbwdrhjxvn.acm-validations.aws.

;; AUTHORITY SECTION:
gbwdrhjxvn.acm-validations.aws. 900 IN  SOA ns-94.awsdns-11.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400

If it is not resolvable, or it does not return the CNAME value specified on the Domains section of the Certificate Status page, then you need to identify where your DNS needs to be updated. Note that DNS TTLs can affect how much time you have to wait for a record to be correctly present on the Internet.