Plugins' network error

Hi there. I’ve been trying to use two Woocommerce plugins that are triggered at checkout and use API keys: Receiptful and FraudLabs Pro. Both don’t work and I get network errors:

1. Error sending customer receipt via Receiptful.
Error Message: couldn’t connect to host. Receipt added to resend queue.

2. Fraud check skipped due network issue.

I checked my debug log and there’s an entry related to FraudLabs:

PHP Strict Standards: Declaration of WC_Integration_FraudLabs_Pro::get_option() should be compatible with WC_Settings_API::get_option($key, $empty_value = NULL) in wp-content/plugins/fraudlabs-pro-for-woocommerce/includes/class-wc-fraudlabspro-woocommerce.php on line 12

Lines 11 and 12 of the said file:

if ( ! class_exists( 'WC_Integration_FraudLabs_Pro' ) ) :
class WC_Integration_FraudLabs_Pro extends WC_Integration {

I’d be very grateful if someone could help me!