Can't connect to Xenapp using Citrix Receiver through Citrix Netscaler Express

Dear experts, I am trying to setup a single Citrix Netscaler Express (VMware) and a single all-in-one Xenapp Server 7.6. Connecting to the Xenapp server using web based is working fine. However if I use Citrix receiver client, it gives a "Your account cannot be added using this server address". 1 thing to note is that the SSL cert for the Netscaler and Citrix Storefront are different. I purchase 2 different public certs to input into both respectively. Therefore they have different URLs. Connecting directly to the Storefront server works fine using the internal URL of the Storefront (bypassing the Netscaler). In the Netscaler settings, I have input the internal URL of the storefront Server. Is there anything I did wrong? I have also tried exporting the pfx file from the Netscaler and input into the Storefront server and change the base URL to match (single and same URL for both). After I do this, both web and Citrix receiver does not work.