When I try using the netherite upgrade it just doesn't work. I can't place the netherite upgrade in the smithing templates place.
I tried using another armour, another smithing table and another upgrade but it doesnt work.
I tried on singleplayer, it worked on singleplayer but didn't work on another aternos server.
Please help. 
*Update*
I tried to use the world in singleplayer and it didn't work. Someone please help