Lexicon Alpha not working

Hi, I have had a lexicon alpha for years now and its not been a problem to me before. I recently upgraded to a MacBook pro and the alpha does not work anymore. I am sure it is just a setting issue.

I have a microphone plugged in with an XLR into the mic port at the back and I'm not hearing anything in Logic, or in the 'input level' when i look at my sound settings.

I know that it is not a microphone problem as I can hear the microphone through headphones that I have plugged into the lexicon itself.

I have done all the obvious things like use different cables and still no difference.

I have also tried DIing a guitar straight into the Lexicon and I still have the same problem.

I hope someone can help me out!

Thanks