Beta launcher won't let me sign in to my account

When I found out there was a beta version for a new Minecraft launcher, I knew I had to try it out, so I did, and I liked it so I kept it, then I went on to play. The next time I opened the launcher, however, I was signed out of my account, and I tried to sign in, but it just displayed a loading screen forever. I know the password and e-mail are correct because I tried logging in on minecraft.net and it worked, also other times when I actually got the password wrong, it displayed a message saying so, unlike this.