Hello, I resolved the problem enabling ActiveX on iE11. My scenario is a PAN-OS 8.1.1 updated. When I tried to access using firewall's IP address I didn't see any pop-up or alert in any place but using the FQDN, an blue forbidden icon appeared in navigation bar. In my case, the Group Policy Objects (GPO) disabled the ActiveX and that caused the message: "Invalid XML response from server". I hope this is useful. Regards.
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