This was asked not so long ago.
It appears that there was a time when anyone using the WordPress hosting system COULD include a utility to play midi files. However, for some reason - maybe the process was being abused, or the owners of the site (WordPress) felt it placed too much strain on thir resources, this option was explicitly removed.
As I understand it, this is now not possible. There may well be no way around this, although maybe they offer extra levels of service, maybe at a cost to you, which might allow this.
You should look into the details of their Terms of Service to see if there are options available to you.