Getting 404 unauthorized error during generating Cert

[Sadhiqiin]

My domain is: http://librenms.aytra.com/

I ran this command:
sudo certbot certonly --email support@ivedha.com
-d librenms.aytra.com
--agree-tos --manual

It produced this output:
Press Enter to Continue
Waiting for verification...
Cleaning up challenges
Failed authorization procedure. librenms.aytra.com (http-01): urn:ietf:params:acme:error:unauthorized :: The client lacks sufficient authorization :: 2620:1ec:bdf::38: Invalid response from http://librenms.aytra.com/.well-known/acme-challenge/UHB_xlH179DDGFH4W2cm5Z8yxkO4ADN4T9txMSiLqek: 404

IMPORTANT NOTES:

• The following errors were reported by the server:

  Domain: librenms.aytra.com
  Type: unauthorized
  Detail: 2620:1ec:bdf::38: Invalid response from
  http://librenms.aytra.com/.well-known/acme-challenge/UHB_xlH179DDGFH4W2cm5Z8yxkO4ADN4T9txMSiLqek:
  404

  To fix these errors, please make sure that your domain name was
  entered correctly and the DNS A/AAAA record(s) for that domain
  contain(s) the right IP address.

[MikeMcQ]

Did you remove an AAAA record from your DNS since that request?
Because the error message stated an IPv6 address but I no longer see an AAAA record

Test result for ibrenms.aytra.com: OK

Would you try that again and show the new results?

[Osiris]

I can still reach the IPv6 address, but there's something weird going on. Sometimes 2620:1ec:bdf::67 responds with a "404 file not found" with, among others, a x-azure-ref and X-Cache HTTP header, but sometimes it responds with a "400 bad request" status with a X-MSEdge-Ref HTTP header and not the other two?

Same goes for IPv4 by the way..

So my advice is: please first fix your webserver and only then try to get a certificate.