Powerline and wdtv live

Hi,

I'm streaming videos on my tv through a WD wdtv live and from my Imac. I was all going fine until I moved the Mac and had to install a PLC XAV5622. Now internet is goig fine, the wdtv live sees my Imac but I can't access it anymore. When I try to reach it, it says that my username and password are invalid. It seems that the PLC puts a barrier to access the Mac.

Would someone know how to fix this ?

Thank you