There appears to be a bug on the UDM Pro that you can encounter while trying to update your WAN IP addresses. The error was similar to “Can’t change IP Address “PublicIP” used in Default Network”
It appears that the issue stems from the Internet Source IP being used in the LAN Network settings.
The way to work around this is to disable the Internet Source IP. However, this is greyed out which keeps us from making any changes. We can however use the Chrome Developer tools to get around this restriction.
- Enable the Legacy Interface. UniFi Network Settings -> System -> Legacy Interface
- Go to Settings -> Networks -> Edit (Select Default Network)
- Open up the Dev tools with Ctrl + Shift + i and select Console
- Paste the following in and hit enter
$$('[disabled]').forEach( a => a.disabled=false )
- Find “Internet Source IP”, Disable and Save!
Swap back to the new user interface and go change the WAN IP address.