I think I've answered my own question. Both psxt's should be usiung RT App mode but client psxt would not show traffic even though it was shown connected to the RT App. The only way to get traffic on the client was to run PSXT in RT Direct mode. I now have the client psxt in RT App mode and receiving data from the RT App by doing the classic delete RealTraffic.ini and restarting. I had to re configure RT App again on restart. It seems we have always had to use this fix right from the early days and not quitre sure after all this time that we have to keep doing this when RT App stops talking to psxt.