Primary Images URL Probelm

I am facing this problem, how to fix this error, i think its about Primary images of post, I have tried by adding featured image but still facing this problem while testing on testing tool.

Check The Error Here Please.
https://search.google.com/structured-data/testing-tool#url=https%3A%2F%2Fwww.thebrokebackpacker.com%2Fstart-freelance-photography%2F

• This topic was modified 5 years, 1 month ago by Muhammad Toqeer Iqbal.
• This topic was modified 5 years, 1 month ago by Muhammad Toqeer Iqbal.

The page I need help with: [log in to see the link]