[Bug] Server Error When Marking Lesson as Complete

[GravityDarkLab]

📝 Description

When a user clicks on “Complete Lesson”, a server-side error occurs and the action fails. The error message is not shown to the user, but it is visible in the logs.

📖 User Story

As a user of the learning platform,
I want to be able to mark a lesson as complete without errors,
so that my progress is saved correctly and I can continue learning seamlessly.

🎯 Acceptance Criteria

• Server error is investigated and root cause identified
• Completing a lesson no longer triggers an error
• User receives correct success response after marking a lesson as complete
• Error is logged appropriately if it occurs again in edge cases

🛠️ Proposed Solution (optional)

• Check backend logic for the completeLesson endpoint
• Add error handling and proper status responses

📂 Affected Components

• Backend API (lesson completion logic)

👥 Assignees

@GravityDarkLab

⏱️ Priority

• High
• Medium
• Low