SEO issue in landing page

we wereusing TML succesfully in our site. Now we have find an issue in our site the google is not fetching our site landing page. while we trying to fetch the site its redirecting to login page. While we search in google we are getting a text like this as description (A description for this result is not available because of this site’s robots.txt – learn more.)

We can fetch siteurl/login successfully using googlr . but it redirecting while fetching siteurl.

Thanks in advance for help.

https://www.ads-software.com/plugins/theme-my-login/