macOS 11.4 and iOS 14.6 impose new transparency requirements for publicly-trusted SSL certificates which were issued on or after April 21, 2021. If your website's certificate does not comply with these requirements, it will not work in macOS 11.4 and iOS 14.6.
Although most certificate authorities issue certificates which comply with Apple's policies by default, some certificate authorities have mistakenly issued non-compliant certificates. You can use this tool to test your website. If your website's certificate is non-compliant, contact your certificate authority as soon as possible to get a new, compliant certificate.
This tool also checks for compliance with Chrome's Certificate Transparency policy.
Cert Spotter monitors your entire SSL certificate portfolio and alerts you about security and availability problems like non-compliant, unauthorized, or expiring certificates.
Your site is not compliant with Chrome's Certificate Transparency policy.
Your site is not compliant with Apple's Certificate Transparency policy.