In the lore of Minecraft, version numbers are usually logical (1.0, 1.1, etc.). Occasionally, snapshots or experimental builds encounter bugs, leading to error codes. Error 422 is rumored to be one of those "glitched" versions that should never have seen the light of day.
This is the most effective fix. The launcher stores metadata about game versions. When that metadata desyncs from Mojang’s servers, you get Error 422. download minecraft error 422