Clicking on Modules goes to 404-page (fresh install)

[jesusChristNovastar]

I have just freshly installed Prestashop through Installatron.
All I did so far was make some changes to the information, contacts
I also removed some unnecessary pages and planned changing the
lay-out of the about-section.

Now, every time I click Modules in the back-end,
it directs to the Front-End 404 Page

Tried Googling for answers but am unable to sort it out.
Was hoping you guys could help

Thanks in advance.