Issue with AWS LightSail connecting to Divi API - Error 400

We are currently hosting our WordPress website on an Amazon Web Services (AWS) Lightsail instance and have installed the popular Divi theme. However, we are encountering a persistent 400 error when attempting to connect the Divi theme to Elegant Themes' API for features like updates and access to the Divi Library. We have verified that ports 80 and 443, which are required for API communication, are open and properly configured on our Lightsail instance. Despite this, we are unable to establish a successful connection to the Divi API, and we require assistance in identifying and resolving the issue causing the error.