Is it okay to mention my failed startup on my resume?
You should absolutely list it.
Startups can fail for any number of reasons, which can be a mix of your fault and not your fault. While there might be some people who are ignorant of just how hard it is to be successful, most people in the industry are not. After all, if VCs aren't able to predict which startups are successful, why should it reflect that poorly on you that you weren't able to predict this?