The following message is show by Plesk pre-upgrade checker when trying to upgrade to the latest Plesk version:
[WARNING] IP address registered in Plesk is invalid or broken: 198.51.100.4
The reported IP address registered in Plesk does not exist on the server.
- Go to Plesk > Tools & Settings > IP addresses
- To update the list of IP addresses and their status, click Reread IP.
- Click Repair on the corrupted IP address.
- If Repair does not help, then contact your network administrator in order to assign correct IP address to the server or remove corrupted IP address from Plesk.
- Continue upgrade.