HELP ME I CANT PLACE BLOCKS THAT COME FROM NETHER UPDATE OR LATER

so ive been trying to build a mailbox and i used a barrel for it and IT IMMEDIANTLEY DISSAPEARED! HELP ME
i have tried to google it up and IT BROUGHT THE WRONG ANSWER!
IF I BUILD IT IN SINGLEPLAYER IT WORKS BUT IF I BUILD IT IN MY SERVER ITS JUST A FENCE
and then i tried to do /setblock ~ ~ ~ minecraft:barrel{Facing:"east"} AND THE DIRECTION DIDNT EVEN WORK! tried it again by replacing { } with [ ] and it worked
please help but not replying to this is not helping