To install the primary SSL certificate, you must complete the pending request, and then bind the certificate to your website, Please follow the steps and Install an Certificate in Microsoft IIS 7.
Step 1: Click Start.
Step 2: Then click Run.
Step 3: Type mmc.
Step 4: Then click OK.
The Microsoft Management Console (Console) window opens.
Step 5: Click the file menu, in the Console1 window, and Select Add/remove Snap-in.
Step 6: Select Certificates, in the Add or Remove Snap-in window, and click Add.
Step 7: Select Computer Account, in the Certificates snap-in window, and then click Next.
Step 8: Select Local Computer, in the Select Computer window, and then click Finish.
Step 9: Click OK.
Step 10: In the Console1 window, click + to expand the folder.
Step 11: Right-click Intermediate Certification Authorities, mouse-over All Tasks.
Step 12: Then click Import.
Step 13: In the Certificate Import Wizard window, click Next.
Step 14: Click Browse to find the intermediate certificate file.
Step 15: Change the file extension filter to PKCS #7 Certificates (*.spc;*.p7b), select the *_iis_intermediates.p7b file
Step 16: Then click Open.
Note : Do not install your Leaf Certificate in this area. Doing so removes your certificate from the list, and you must reinstall to correct the problem.
Step 17: Click Next, in the Certificate Import Wizard window.
Step 18: Select Place all certificates in the following store.
Step 19: Then click Browse.
Step 20: In the Select Certificate Store window, select Intermediate Certification Authorities, and then click OK.
Step 21: In the Certificate Import Wizard window, click Next.
Step 22: Click Finish.
Step 23: Click OK.
Step 24: Close the Console 1 window.
Step 25: Then click No to remove the console settings.