Error in "/onepagecheckout#opc-billing" when clicking "continue" in "Billing address" returns to "/cart"

The error occurs when I have a subdomain configured for my store. For example:
store.marketing.com.br

When adding products and going to the cart and checking out I am taken to "/onepagecheckout#opc-billing". The moment I click "Continue" in "Billing address" I am taken to "cart/" and then it stays in the loop.

*I can see when inspecting the console, in Chrome, an error appears very quickly and I had to be a ninja to take a screenshot that says the following: "The page was loaded over HTTPS, but the request was insecure XMLHttpRequest"
* This is only happening when I have a subdomain configured store.marketing.com.br
* I configured the store URL correctly in "Admin/Store/Edit/1", that is, "https://store.marketing.com.br" and also checked Enable SSL.
* nopCommerce version 4.60.6

One little thing is domain should have a slash at the end
https://store.marketing.com.br/

Yes. I put the bar too. I just forgot to mention the "/" at the end of the domain. The problem still occurs.

Is your website behind a reverse proxy ?
https://github.com/nopSolutions/nopCommerce/issues/5126