No audio out, Firestudio 2626

Hi, i'm very confused because i have a problem with my presonus firestudio2626, today i have connected, with a optical cable, the firsestudio with a ezbus event for use his inputs in the firestudio... when i played the firestudio the audio didn't go out. I have disconnected the ezbus but the problem has not been solved. I tried to check setting in logic pro 8 but are ok and trying to change the output I realized that the audio comes out by the pc but not by the firestudio...Whath can I do to solve the problem?