I tested a clean project on 5.5.4, created a new actor and placed it on the default level.
New actor contains a beginplay event playing the sound + attenuation. all options are default.
It works for me.
Can you do the above steps and place the actor on your level with your sound file? (new actor, begin play, play sound. (i played it at location 0,0,0 though)).
If it then still does not work, something on your project level or assets differs from the default which causes your problem. To further rule out external causes you could create an entire new clean text project like I did. If the problem then occurs, there is something more complex going on (since it works for me, on my device and my OS).