Hi, although I personally cannot provide discord/voice/chat to investigate, but in general and for this forum it might provide useful if you could :
State what MAME version and variant (official MAME, MAMEUI, etc) you are using, on what platform (and version) you are running MAME (Windows, Linux, Mac, etc.), some hardware specs (xth Gen Intel i7 4GHz, 8GB RAM, etc.), and what the name of the game is that you would like to play.
Furthermore, if you could provide the following that would be helpful:
1.) Steps taken to reproduce the issue.
For example: Start the Windows Explorer, browse to the C:\Mame folder, and doubleclick on mame64.exe. Use the MAME internal menu to browse to 'pacman', and start that game by doubleclicking that title/name.
2.) Expected result.
Example: Pacman starts, and I can play the game.
3.) Actual result.
For example: If you get an error message, what is that exact message ? Do you get a black screen that stays there forever but the game does not start ? Does the entire computer freeze and you have to reboot ? Something else ?