1.Teleport to x=101,y=11,z=101.

2.Type"/execute as @a[x=100,y=10,z=100,distance=..5] run say 123", "/execute as @p[x=100,y=10,z=100,distance=..5] run say 123", or "/execute as @e[type=player,x=100,y=10,z=100,distance=..5] run say 123".

It says "No entity was found".

But if I type "/execute as @e[x=100,y=10,z=100,distance=..5] run say 123", it works.