Lack of feedback is a major red flag for investors for two key reasons.

First, it signals risk. If VCs have never heard of you before, it doesn’t matter how much they like your idea; they’ll be uncertain whether it will work. Maybe the market isn’t as you say. If you don’t have any market feedback, then you are feeding investors a certain level of risk. 

Second, it tells investors that you’re an early-stage company. If you haven’t figured out if there is a market for your product, that tells investors that there’s a long road to product-market fit. A longer road to returns means investing in a company that will take longer for the returns to show up. That makes the next round of financing more difficult. 

Moreover, avoiding feedback can tell potential investors that you’re a bad founder. Not seeking feedback can signal inexperience, closed-mindedness or lack of interest in user input. Investors want founders who can get things built quickly, ask for feedback and iterate. Those who don’t iterate after feedback often don’t make it in the long run.