Hey wurst_client_user, sorry for any misunderstanding but the SessionStealer was patched years ago. Mojang patched this security issue on their servers and thus, it no longer works. Here's some additional reading if you're interested: https://wurst.wiki/sessionstealer
And about your username, it might be a bit problematic since your handle is just
wurst_client. Someone might look at that and think you're the developer of the Wurst Client. Would you mind changing it to avoid any potential mix-up? Thanks!