Hii

This issue of not being able to login might be due to some network error. Make sure you have a strong network connection. Make sure you have entered the correct details i.e login ID and Password.
Even if you face the same issue, then try to clear the CACHE and again login. Also if you are using private browsing window, i will suggest that you close that and try logging in through normal browser window.
Even after this if the problem persists, then contact the aiims authority and ask them about the same.

Hope this helps.
Thanks!