This is being caused by the Plesk upgrade script removing some files from the psa-api-rpc package. Please remove the psa-api-rpc package and reinstall using the Plesk installation script in order to replace the missing files.Error retrieving version from Plesk API: Error communicating with Plesk API: are the packages psa-api and psa-api-rpc installed?
Other things to check for include:
- Were there any recent changes or upgrades to your Plesk server made?
- Do you have Firewall rules enabled on the server? [list]
- If so - is there a rule blocking access to port 8443?
- If so - are there rules ahead of that permitting access to port 8443 for source IP 127.0.0.1?
[*]In the Plesk Panel - Under 'Security' / 'Control Panel Access' - is the default preference set to 'Allowed' or 'Denied'[/*]
- Is there a network entry for 127.0.0.1