ERROR: Cannot determine exchange rates

I’m using version 3.10 of the plugin but am getting the following error:

“Bitcoin payment gateway is not operational: ERROR: Cannot determine exchange rates (for ‘GBP’)! Make sure your PHP settings are configured properly and your server can (is allowed to) connect to external WEB services via PHP.”

I’ve looked at every thread I can find and there still seems to be no solution. I’ve used the code:

<?php echo file_get_contents ('https://api.bitcoincharts.com/v1/weighted_prices.json'); ?>

which works fine and I get plenty of results – including the the ‘GBP’ currency I wish to use. I’ve considered the servers being down and so have tried throughout the day but still with the same failed result.

I don’t know what else I can possibly try. Any ideas?

https://www.ads-software.com/plugins/bitcoin-payments-for-woocommerce/