555 is still in beta, so I wouldn’t be surprised if something doesn’t work. That said, I haven’t experienced what you have (on GTX 1070 TI), though using 555 causes lots of kernel errors for me. Checking dmeg might reveal something in your case as well.
When everything closes, are you sure that’s the lock screen and not the login screen? It sounds like cinnamon is crashing, which means you’re automatically switched back to the display manager (login screen). This can sometimes show the boot logo while it’s switching, happens on my laptop as well, noy sure why that is. If it is crashing, you might find the cause in the logs, run
journalctl -e
anddmesg
to check for errors