Cant play videos or songs when i connect external sound card

Hey guys,

this problem started a week ago -+, before, everything worked perfectly.

but in the last week, i can watch video's on youtube or hear songs on Rdio then pause them connect the card and then when i press Play it shows a loading sign til i disconnect the card. just cant hear or watch online videos/songs. its even happend on Itunes.

hope you know somthing about that, just say for more information.

- OSX Yesomite 10.10.2

- the card connect with USB cable

thank

Noy