Target Selectors in say command are not mentioning names

When using target selectors (@a, @p, etc.) in say command, it is not mentioning names.

To reproduce:
*For example, if your ign is Mark, type the say command like this

/say Hello @p(or @a if there are multiple players)

What I expect:
In chat menu, "Hello Mark"

What really happened:
In chat menu, "Hello @p"

"I can't search here if someone reported already. If there are any, please resolve this as duplicate"

Device: Samsung Galaxy Grand Prime