Cannot login to Couponpress admin page

Hello! Yesterday it was working, but today is not working. When I want to login to couponpress admin page, I type site.com/wp-admin and it usually redirects me to the wp-login.php
There I type my username and password and after it it usually redirected me to Couponpress admin page.
But today when I type my username and password, it takes me to home page.
The url becomes like this:
?testcookie=1&redirect_to=http%3A%2F%2Fsite.com&rememberme=forever&log=username&pwd=password=Enter
And if I again type site.com/wp-admin, it redirects me to wp-login.php
So I cannot enter my couponpress admin page.
Please help.