Cannot activate version 2.7.10

I just install plugin version 2.7.10 but when I try to connect my account error occured: “The website of this connection is not available”.

I checked server error_log and I found this error:
AH01071: Got error ‘PHP message: PHP Warning: Undefined array key “merchant_id” in /opt/bitnami/wordpress/wp-content/plugins/sumup-payment-gateway-for-woocommerce/includes/class-wc-sumup-logger.php on line 25; PHP message: PHP Warning: Undefined array key “merchant_id” in /opt/bitnami/wordpress/wp-content/plugins/sumup-payment-gateway-for-woocommerce/includes/class-wc-sumup-logger.php on line 25; PHP message: PHP Warning: Undefined array key “id” in /opt/bitnami/wordpress/wp-content/plugins/sumup-payment-gateway-for-woocommerce/includes/class-wc-sumup-onboarding.php on line 62’, referer: https://motoline.it/wp-admin/admin.php?page=wc-settings&tab=checkout&section=sumup&validate_settings=false

Can you help me?

The page I need help with: [log in to see the link]