Hi @Islambadry
Could you try contacting our technical support?
Other than that, some clues below 
Please make sure the configuration is exactly the same as shown here:
Also, please make sure that navigating to http://localhost/ brings you to the default page of the ISS.
At last, one user found out that the problem was the ApplicationPoolUser which did not have access to the database. You can check for that too
ashokkarale
lrtetala
SorenB
shilpashree.mohanty
ppr
Anil_G
htanaka1
shaik.muktharvalli1
SA64