Warning: file_get_contents

Hello,
First, great plugin! Its been working perfectly.
But, I just started getting an error thats messing with our site, its displayed at the top of the site. If the plugin is deactivated the warning/error disappears:

Warning: file_get_contents(https://www.cryptocompare.com/api/data/coinlist/): failed to open stream: HTTP request failed! HTTP/1.1 403 Forbidden
in …/wp-content/plugins/cryptocurrency-rocket-tools/cryptocurrency-rocket-tools.php on line 100

Warning: session_start(): Cannot send session cache limiter – headers already sent (output started at …/wp-content/plugins/cryptocurrency-rocket-tools/cryptocurrency-rocket-tools.php:100) in …/wp-content/plugins/wordpress-social-login/wp-social-login.php on line 64

Warning: Cannot modify header information – headers already sent by (output started at …/wp-content/plugins/cryptocurrency-rocket-tools/cryptocurrency-rocket-tools.php:100) in …/wp-content/themes/AT/framework/class/class_layout.php on line 433

Any ideas of what can cause this error?