Plesk interface is secured with the default self-signed certificate - the option Tools & Settings > SSL/TLS Certificates > Certificate for securing Plesk is set either to Unknown or default certificate from server pool.
On a machine with macOS 10.15 Catalina, accessing the Plesk interface in Chrome or Chromium-based browser fails with the error
ERR_CERT_INVALIDand there is no option to ignore the error:
In macOS 10.15, Apple changed requirements for trusted SSL/TLS certificates, and the self-signed certificate generated by Plesk does not comply with these requirements.
This issue was recognized as the Plesk bug PPP-44839 which is planned to be resolved in the next Plesk Obsidian update.
Until the bug is fixed, use another browser for accessing the Plesk interface - for example, Safari or Mozilla Firefox.