It is recommended to revert the GMI parameter SVSRVSYS back to its default. There is no need to set that parameter to anything.
By default, the GMI instance will communicate with the SYSVIEW on the local system where GMI is running.
The remote SYSVIEW needs to have an XSCONN group defined that includes the system's name that it wants to communicate with. In this case, it appears that there is a XSCONN group defined.
However, that XSCONN group also needs to have the local system included in that group if an attempt is made to connect to the local system.
So, on the XXXX system, it's needed a XSCONN group defined titled XXXX and includes an entry called XXXX.
To get Vantage working on another system, it is needed to follow the same steps as the ones taken for XXXX.