problem when plugging a guitar processor pedal(screech noise

I’m using Audacity 2.1.3 and my OS is Windows 8.1 pro.The problem is that whenever I plug in my guitar processor pedal(zoom 707ii) into my PC for recording in Audacity I get a loud screeching sound in my headphone.All the instruments that I’m using are tested to be fine including the cables.What might be the problem??Please could anyone help??I would be really thankful :slight_smile: .I obtained the software via the .exe installer. Thank you.

Check that “Software Playthrough” is off (not selected) near the bottom of the Transport menu.