Wiim Home App - basic question

[prossisat]

Hello.
Just a basic question.
My tracks are all manually tagged, (I hope) in a standard way and without errors.
Using Wiim Home App as DLNA client I can see all the tracks without problems.
Unfortunately, though, for each track I see the Composer tag, instead of the Artist tag.
Why?
What can I do to correct this problem?
TIA