Endless Redirect with Ultimate Members Plugin When the number of users exceeds12

Hello Support and other users,
I have been having frustrations with Endless Redirects after signups/signins on my website for a couple of weeks.

But today I realized where the problem was: that the users must not be more than 12, less than that, it’s just fine.
The website only has 2 user roles, namely the student and teacher, other than the admin.

It’s the student user account that gets affected with endless redirects if the overall users exceed 12 in total number.

My website is designed such that the normal url upon signin looks like https://mywebsite.com/account/

However, when the users exceed 12, this changes to https://mywebsite.com/account/?members_page=1 with endless loops

I am using Version 1.3.57 which I cannot update because if I do, several parts of the website cease to work. Please help or suggest how I change these redirects or increase the number users to at least 1000. Thank you