I keep trying to create new landing pages and it keeps overwriting another landing page. Is there a limit to the number of landing pages or is this a technical glitch? I managed to create a third one and when I tried again to create a fourth one - it overrides my second one.
Thank you for reaching out to the Community about your sign up form! I'm sorry to hear of this experience you're having trying to create a fourth form. There is no limit to how many landing pages an account can have. You can create as many Landing Page Sign-up Forms as you need and control the appearance, information collected, and list options for each. I took a peek at your account and was unable to replicate this experience you've described.
In fact, I was able to create a new Landing Page Sign-up Form called Support Test Sign-Up Form 8/7/2018. Have you tried working in a different browser? If you have not yet tested your browser I would suggest creating your new landing page sign up form in a different browser or a private/incognito window.