Captcha does not show up. (OpenRealEstate Version. Pro )

Hi All,
Just install open realesate Version. Pro. And it seem everything looks good so far.
But all the captcha image in every page does not show up.
Can you guy please advice how to fix this ?
Thanks
Just install open realesate Version. Pro. And it seem everything looks good so far.
But all the captcha image in every page does not show up.
Can you guy please advice how to fix this ?
Thanks