External DNS is used for the domain example.com;
Cannot renew wildcard certificate with the following messages received by Plesk administrator:
CONFIG_TEXT: Cannot renew LE: Skip wildcard certificate renewal for the domain 'example.com'. TXT record could not be created automatically. Try to renew domain certificate manually.
TXT record has not been added or updated on domain example.com on external DNS side: when external DNS is used it is required to add TXT record manually each time to re-issue Let's Encrypt certificate.