Ok, let me be upfront first that this blog post may not solve the specific problem you are having. This is a description of the problem I was having with my BiLiPro FootMouse and the solution I discovered. If this doesn’t help you, I’m sorry and good luck with your search for a solution!
“Stop waffling and tell me how you fixed it”:
There is a small circular yellow button on the left side of the buttons panel (officially called the ‘FootButtons’). See the small yellow button on the left side of the FootButtons in this photo:
The button has the words ‘Push in To Define All Buttons’ above it. I found that when this was pressed in the Left Click, Left Double Click, and Right Click buttons all stopped working. Simply press it to make the button pop out and the buttons should start working again
This solution worked for me on a PC running the Windows 10 Fall Creators Update (Windows 10 version 1709).