Symptoms
The following message is shown by Plesk pre-upgrade checker on attempt to update Plesk:
[WARNING] IP address registered in Plesk is invalid or broken: 203.0.113.2
The IP address 203.0.113.2 is marked as invalid in Plesk at Tools & Settings > IP Addresses and the following message is shown:
This IP address is not configured properly
Cause
The IP address shown in the warning message is registered in Plesk, but does not exist on the server.
Resolution
Go to Tools & Settings > IP addresses.
Click Reread IP to refresh the information about IP addresses.
Select the broken IP address and click Repair.
If Repair did not fix the broken IP address, select this IP address and click Remove.
Once all the IP addresses are properly configured, continue with Plesk Update.