Unable to change robots.txt for my app


For my app that is published at https://sparts.softr.app I am unable to change the robots.txt file.

I have altered it in Settings>SEO>robots.txt as:
“User-agent: *
Allow: /”

But when I publish the app and open https://sparts.softr.app/robots.txt, I am shown:
“User-agent: * Disallow: / User-agent: Twitterbot Allow: / User-agent: FacebookBot Allow: /”

I am not able to understand, why is this happening? Somebody please help, my app is not getting indexed by google due to this.

Given softr.app subdomains are shared the crawling is disabled for them please add your custom domain to enable it