It looks loke these are massively under- exposed.
It would help to know what mode you were shooting in (M, Av,Tv etc) and what your settings were. I.e. aperture, shutter speed, ISO.
Also what lens were you using please?
Right. Sounds like you're a newbie. Didn't even say what model camera you have. "Eon mk 2" is not it.
Do you have the manual for your camera? Download it from Canon, or buy a printed manual on eBay, from UsedPhotoPro or KEH. Start by resetting your camera to factory defaults. Then set the camera to P(rogram) mode and see if you get good exposures. There is a lot to learn about your camera!
Start by placing the camera in automatic mode (on the camera's mode dial, switch it to the green A symbol surrounded by a box).
If that also leads to issues, you'll probably want to then reset the camera back to its default settings. Once we know the exact model number of your camera (e.g. EOS 5D Mark II), we'll be able to provide details on how to reset it.
To reset the EOS M50 Mark II, refer to page 633 of the User Manual.
Basically, bring up the "Wrench" Funcion settings and select #5. The top item in that menu should now be "Reset Camera"
12/05/2023: New firmware updates are available.
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.