Why can't I flash any custom roms in TWRP?

[Android Central Question]

Whenever I try to install any custom roms, I get the message: updater Process ended with Error 255. The only rom that I managed to install after factory resetting is Ressurection Remix (Version RR-N-v5.8.3-20170415-athene-official), Android 7.1.2.

My TWRP version is 3.2.1-0 + Motorola Moto G4
I can flash zip files like Magisk or SuperSu, just not rom files.

Thanks in advance!