This was their reply.

Hi Sri Harsha,

I hope this email finds you well, and thank you for taking the time to apply to Toptal.

After carefully reviewing your submission, we have decided to pause your application. Your time is valuable, so before you start our screening process we make sure we have jobs available that match your profile. However, our network has limited current opportunities that match your skills and/or availability. If you have additional skills you haven't listed on Toptal which may be relevant to our clients - or if you are willing to commit a higher number of hours - please let us know.

Our clients' needs are constantly evolving, so we encourage you to restart your application in six months. At that time, you can reopen your application by signing in to Toptal.

If you have any questions, please don't hesitate to contact us at any time.

I’ve already selected the 40hr/week in the application which was the option with highest number of weeks. So it can’t be related to that. I’ve introduced myself as a backend developer with proficiency in Java and Python, familiarity with JavaScript. I’m thinking, it should be related to that. Is it that hard to find freelance/remote work as a pure backend developer?