I cannot import reviews from Amazon

Hi! I installed the chrome extension.
I input the domain and then the secret key and click save.
After clicking save, the secret key field becomes blank. Not sure if this is normal.

Then I set the import review to “a special product”.
Then I go to an Amazon product page, and click the import button.
Then, I keep getting this pop up when I try to import review from amazon:
Please add domain that you want to import reviews to. Your site must have a valid SSL Certificate and install WooCommerce Photo Reviews Premium to use this extension.

My site has SSL and have the premium plugin installed. So I don’t know why I cannot import.
Please advise. thanks.