What caused your startup to fail?

I'm building a tool to help founders to solve the need to determine what problems their target market are experiencing, scrap/prioritise the problems customers need most/least and determine/test the most effective solution, without wasting money/time on building a solution nobody wants.

it is a productivity tool based on the design thinking process.

For more info visit https://www.prepxus.com

I have done a few customer interviews in the past to get the tool where it is, but in addition to customer interviews, I would like to work with entrepreneurs on building a solution that entices others to partake in that initial discovery phase we seem to avoid until it is too late.