About once a week I get the question -"What do you think about automated mastering services such as Landr?". There's a very short and a profoundly more detailed answer. I tend to go for the short answer since the real answer is a lecture and I'll probably lose you half way through. The short answer is: Remove mastering from that sentence and I'll tell you it can be a useful tool to test your mix. Keep mastering in the sentence and I'll tell you that it sucks monkey balls.
Luckily I stumbled across an article written by Mastering Engineer Justin Perkins (Mystery Room Mastering) that pretty much cover everything there is to be said about Landr and similar services, so from now on I won't answer, I'll just give people this link: