After Oracle Linux upgrade, getting "PuTTY X11 proxy: unable to connect to forwarded X server: Network error: Connection refused"

After upgrading a server from Oracle Linux 7 to Oracle Linux 8 via leapp, one of our users who will use X sessions for testing and DB management is getting a message when he logs in of "PuTTY X11 proxy: unable to connect to forwarded X server: Network error: Connection refused" I didn't do anything with the X server, and he is the only person getting this message. Any ideas on where to start to get rid of this error?