However, you can still view your content offline within the official app. Here is a post draft you can use to share this information or ask for help, followed by the official offline viewing steps.
Downloading videos from Classplus-powered apps is strictly regulated by the platform's content protection policies. Official downloads are typically restricted to "offline viewing" within the mobile app itself, rather than saving to your device's gallery. Official Method: Offline Viewing in the App Download Classplus Videos