“Internal Server Error” Login

Hi there,
When I try to log-in at “/membership-login/” page I get an “Internal Server Error”.
The curious point is that I just get this error in Chrome!
I have tried in FF and Safari and in both it works great!

I don’t have any Console Error in Chrome. I also have plugin Debug enabled but no error trace appears!

WP version is 4.4.5

Thanks in advance!
Tolo