What would be the reason for a registration page to hangs after submit? For some reason whenever i try to submit a new user registration (on a fresh drupal 7 install), the data is correctly sent to the Back end but the page doesn't seem to redirect to the intended location (by default the home page)but instead seems to endlessly submit. 

I am pretty sure this come from my testing server as it does it even on a fresh drupal install.
Is there anything that would come to your minds on what could be the cause of this problem ?
We are using ubuntu server with all latest software updates.
Check memory_limit for your Drupal instance.

On settings.php add this line

ini_set('memory_limit', '128M');