Can't integrate klaviyo get SSL error

I have a free account with profreehost with a paid domain I ended up securing the site with sslforfree.com. The only problem I have I can't integrate klaviyo with woocommerce. I tried it with the klaviyo plugin and it does create the REST API within woocommerce. It then takes me to klaviyo which gives me the error Unable to access https://site.com. SSL error. I have no idea why I'm getting the error I'm able to access the site and it has the padlock with no issues. I even installed Really Simple SSL yesterday to see if the issue would be fixed it still gives the same issue. In the REST API within woocommerce I have dsers and Ryviu they integrated just fine the version of wordpress I have is version 5.9.3. Any help?