Failed to load mods: Error while running setup for entity prototype "100-cerys-mixed-oxide-reactor" (reactor): next_upgrade target (bob-nuclear-reactor-2) must have the same fast_replaceable_group (nuclear-reactor != mixed-oxide-reactor).
2 mods conficted:
-More Quality Scaling
-Maraxisis

This seems to be an incompatibility between some Bob mod and Cerys. Can you check if this issue also occurs when More Quality Scaling is not active?

No. I can load normally. But when I added More Quality Scaling in, it crashed with error above

Could you post a list of your active mods, or a save file with all of those enabled?

I found the issue - should be fixed in 1.4.3.

Thanks