Captive Portal will not show up disclaimer page. FortiOS 5.6.4

Hi all,

I have a FG500d running Ver 5.6.4 and seem to be having issues getting the disclaimer page to even show up.

Tried both on windows devices and Android as well. This is for a guest WiFi and is using tunneling back to the FG500.

I have done this before with no problems even at 5.6.3 on a FG60d.

Thought it might have been the problem whereby you have to look at an http site not https for the page to pop up. Checked browser popup suppression.

Disabling the captive portal is OK so I know back end connectivity is OK.

Anyone seen anything like this? Not a bug?

Cheers & thanks,

Simon.