PayPal standart is unavailable when checkout on embedded product. Work only if Paypal standart is the single method and choosen "Auto select" - (to be selected by default). How can i resolve problem?      On Abantecart site (not embedded) it's working ok.

Also there is a problem with PayPal Express. -
When i'm testing connection, give me this error: "PayPal error: Security header is not valid. Please check your API Credentials and try again. Also please note that Test mode is OFF!"

Logs: 2018-04-09 16:59:09 - App Warning: AbanteCart core v.1.2.12 PayPal Express Checkout Error: Security header is not valid. Test mode = 0. in /home/c/myserver/mysite.store/public_html/abantecart/extensions/default_pp_express/admin/controller/responses/extension/default_pp_express.php on line 84