Hello Truong Pham,
Thank you for using our services.
Sitefinity's Project Manager needs to be run into 32 bit mode and in the Classic App pool. To enable the Project manager to work in a 64 bit OS you should enable 32 bit application for IIS. Right click on the Application Pool and select "Advanced Settings" then "Enable 32-bit Applications" (see attached image). Also, try changing the application pool for the telerik/Sitefinity3.7
from Default to Classic .NET AppPool. Check out whether you have configured your web server to handle ASP.Net extensions. Make sure that ASP is installed (by default, ASP is not installed with IIS).Note that only the Project Manager has to run in 32 bit mode and using the Classic App pool. After you run it and create a website, you will be able to run the website in Default App pool and in 64 bit mode.
the Telerik team