Sucuri Firewall blocks access of bad actors to your website. The Website Application Firewall (WAF) may occasionally also block RabbitLoader IP addresses if not whitelisted.
Open the WAF dashboard, and select the website that you are using with RabbitLoader. If you want to do this for multiple websites, you need to repeat the steps for each website.
Navigate to Allow IP Addresses section, and enter RabbitLoader IP addresses. Please refer to this page for the latest RabbitLoader IP address.
Choose Permanently from the dropdown and click on the Allow button to save the whitelisted IP addresses. We also recommend checking the Sucuri KB for the most recent UI navigation and other ways to whitelist the IP address.