when buddypress installed, wp-signup.php Re-directing to home page

Hi, I am having issue with wp-signup.php. when buddypress plugin is installed in my site then wp-signup.php this page redirects to home page. Without buddypress plugin wp-signup.php working fine. But I need buddypress plugin also. So how can solve this issue?
Note: I am using latest wordpress version, I setup pretty permalink option, I also tried with twenty fifteen theme, but still having this issue.

Thanks in Advance.