By default, all CA servers are in pending mode and you must manually approve each signed certificate request. Since this method is not feasible for bulk requests, enable the automatic approval of signed certificates.
From Server Manager, click Tools > Certification Authority.
From the left panel, right-click the CA, and then click Properties > Policy Module.
From the Request Handling tab, click Follow the settings in the certificate template if applicable, and then click OK.
Restart the CA service.