Problem: Error: Let's Encrypt is unable to validate resource challenge because the client lacks sufficient authorization.
Cause: This problem occurs while installing Let's Encrypt certificate through the Hosting Controller Panel and when limits for issuing certificates are reached on Let's Encrypt servers.
The only way is to wait until limits will be reset on Let's Encrypt for SSL certificates. To get more information regarding Let's Encrypt limits follow this URL: Let's Encrypt | Rate Limits
The most common rate limit of 50 certificates per domain per 7 days in a place that is set by Let's Encrypt. As the limit is defined by Let's Encrypt directly and cannot be managed through Hosting Controller. To overcome the issue, wait for a week period to pass and then try to install the certificate on the same website through the HC10 control panel.
For any further queries please contact firstname.lastname@example.org