7th Gen Normal type moves have no effect on Ghost types for some reason

[MudkipLover2005]

When I was doing the Ghost trial and had my normal types I tried to use a Normal move, but it said "It doesn't affect [Pokémon]" for no reason. I looked and it might be a glitch. What do you guys think? Was it a glitch? Or is it meant to happen?

P.S. This is my first post so I maybe a bit worried but I am not scared

 

[Percy]

When I was doing the Ghost trial and had my normal types I tried to use a Normal move, but it said "It doesn't affect [Pokémon]" for no reason. I looked and it might be a glitch. What do you guys think? Was it a glitch? Or is it meant to happen?

P.S. This is my first post so I maybe a bit worried but I am not scared

i assume its your first time playing a pokemon game? nothing to fear since that's how the type matchup works. normal moves doesn't affect ghost types. ghost moves doesn't affect normal types etc. etc.
read more about type matchups: https://bulbapedia.bulbagarden.net/wiki/Type/Type_chart

happy playing :)