Problem with “Invalid sdk meta” - spinning animation without loading any further data

I'm trying to integrate your plugin on my store.
I saw that payment buttons.  
When clicking on any button, there is only spinning animation without loading any further data. No error message is provided.

    In developer tools I saw the broken request (400) which says:

Invalid sdk meta: eyJ1cmwiOiIvL3d3dy5wY...

Minification removes HTTPS from this script
<script src="//www.paypal.com/sdk/js?client-id=AQ-
this is correct script
<script src="https://www.paypal.com/sdk/js?client-id=AQ-

Disable minification in the nopcommerce store and try again.