I could not be able to know what is the problem in the front page. Would you mind sharing us your admin credentials in a secure note so we could check your setup closer.
Please review this thread to get to know how to get support:
Meanwhile, I have check your portfolio items and I can see that you have inserted an image in your portfolio item contents. The problem is that there is a big rectangular box above the content. This area is suppose to hold the featured image. The thing is that, you did not insert a featured image for you portfolio items. The featured image will also be used to display images in the portfolio page. To resolve your issue, you will have to edit each of the portfolio items and insert a featured image.