Some things you can keep in mind in case these options don't work for you c:
o Try logging into a different browser, preferably Chrome / Firefox.
o If your username is longer than 16 characters then it won't work no matter what you do.
o If the tab is kicking you off because it says that you have inputted the incorrect user / password then it might be a possibility that your information isn't matching up. ( Happens to me sometimes when I log into another account and I mix up the user / password ).
o Try logging into your cellular device or even another computer to see if the problem persists.
These are just some things you can try ^^
Sorry :c
But just keep your eye out for it and you'll be able to catch registration. Good luck floof ~! c: