Rejection: It's Nothing Personal
Maybe you're thinking about getting into voice acting, but you're worried about the potential rejection you may face. This is a pretty common anxiety, and I've met a few people who gave up early in their pursuit of this as a career because of it. So let's talk about rejection, the realities of it, and how it's not actually the scary monster one may think it to be.

First and foremost, it's important to understand that you will get rejected. That's just part of getting into anything which requires you to audition for a role. Dozens—or hundreds—of people will compete for the same part, and only one person will be cast, so the odds aren't really in your favor (still a better chance than winning the lottery, though). There are things you can do to help increase your odds, but ultimately the choice boils down to what the client or casting director has in mind for the role. You might be just as skilled as the talent who was cast, but their voice is just the better fit. It's nothing personal against you, and maybe you'll be the one cast next time and that talent will get the rejection. Like, maybe they're a better fit for “angry customer” in this commercial, but you'll be a much better “confused frog” in a video game.
Now, if you are never getting cast, then perhaps it's time to step back and reevaluate some things. Consider the quality of your recordings, maybe get them checked out by an expert, and see if there's something wrong. Maybe your acoustics are off and there's a strange resonance, or maybe something's faulty in your equipment and there's a hum or distortion. If your recordings are clear and of good quality, then there are a few other things to consider. And in order to consider them, you'll have to set your pride aside.
First, maybe you're not applying for the right kind of jobs suited to your voice. You may have a wide range of voices you can do, and so think that translates to auditioning for anything you want. However, there may be some types of jobs that are actually more suited to your voice talents than others. Plus—and I'm sure you might not want to face this, but it's important to consider—you could actually not be the best at some of the things you think you can do. Maybe you're convinced you do a fantastic “wise grandparent” voice, but everyone else thinks you sound like a kid with a cold (using this example, because I know I personally fail at grandparent voices). Training with a good voice acting instructor can help you pinpoint your strengths and weaknesses and identify what types of jobs you'd be most successful in auditioning for.
Speaking of training, that may be the biggest thing you need, if none of your auditions have resulted in getting hired. It doesn't matter how much training you've already had; everyone can always benefit from more. You may be incredibly talented, but training is the polish you'll need to really help your delivery shine. It'll also provide you with the opportunity to speak with a successful and established voice actor, who can give you even more insight and advice concerning your auditions. Plus I cannot stress enough how much it helps to have someone outside your own brain listen to your voice and delivery and assess it (that's how you learn you can't do that grandparent voice as well as you thought).
The biggest thing to remember about rejections, though, is that you shouldn't let them get you down. Like I said, they are just a regular part of this kind of work, and some weeks will have more than others. Don't take it personally, and just move on to the next audition. Understand that you just weren't the right fit for that job, but it doesn't mean you won't be perfect for the next one.