The Black Ops 6 beta is still in development, so it's normal to experience crashes and glitches.
Try restarting the game, using a wired connection for better internet, closing other programs using internet, and verifying the game files for any errors.
If these solutions don't work, the server might be overloaded due to a large number of players, but the developers are actively working on fixing these issues.
Keep an eye out for updates and remember that the beta is a testing phase, and they're using your feedback to improve the game before its official release.
