message security image not displaying - by: Iain

Hi
On my site
www.ukholidayhomesforsale.com/ciputra-a1
The security image does not display, thus messages cannot be sent
This is the same in -
property listing
Agent contact form

OSproperty 2.9.8
joomla 3.5.1
template OSP Real Homes - Default
I have also tried joomla template Beez3 and is the same
And tried different template layouts and themes and is the same
Can you please help
Thanks
Iain