Go to settings > network > reset network settings to default it could fix it as this sounds network related. Could you please upload DebugOutput.log and post it; its on the root.
Yeah we're going to have to see DebugOutput.log, it should indicate the issue. Also, check if fake-live is enabled as that's one thing that I'm sure we all forget to disable when switching from Online Play > Offline Play
Wait... I think your KV is a Slim KV, you should try and convert it to a Phat KV. I just found this tool here I haven't tested it but I think there is a small chance it could fix your issue
Don't worry sorted it out. The stealth server he was on is not working we got xblse running just fine