Please follow the below steps to enable the popups of the Cortex Site on the Internet Explorer:
1. Open Internet Explorer, select the Tools(Gear) button as shown in the below screenshot, and then select Internet options to display a dialog box.
2. Click the "Privacy" tab on the dialog box, click the "Turn on Popup Blocker" button to add a tick and then click the “Settings” button to open the Pop-up Blocker Settings dialog box.
3. Type the website address "https://Cortex.acr.org" in the address field. Click the “Add” button and then click the “Close” button on the Pop-up Blocker Settings dialog box.
4. Click on "Apply" and "Ok" on the Internet Options dialog box.
Please check the attached video for the reference.