Founders face investor rejection all the time. It's part of the game. However, how founders handle this investor rejection is key to their success or failure. 

Investors reject an investment for a wide range of reasons - many of these being more centered around what is right for their fund. Depending on their fund size, number of idea stage bets that have in the current fund, number of late-stage bets they've taken, sectors where they are over-indexed and many such factors go into an investor rejecting a perfectly good company. 

But founders often take rejection too personally. Some spiral into self-doubt and some get turned off by the investor route. Neither of these actually helps the founders at all --- what might go a long way is to take valuable rejection reasons that may go into addressing any gaps they may have, filter the rest and move on without self-doubt or frustration. 

There are far more founders than there are investors and even the most successful founders of our times all faced some level of rejection.