Extreme portable SSD >. Numark 500 NDX media player

Hi. I am new to all this. I bought a Sandisk Extreme portable SSD to store music and connect my SSD to my Numark 500 NDX media player. when I connect the SSD to Numark 500 NDX its scan the SSD and delivers a message on the Numark with ‘PA - 5 EL’. ? there is music files on the SDD what can I do to get round this please?

Thank you to anyone that can help?