External courses that can be used within the academy via coupons have a max quota and an expiration date. The coupon quota are being decreased every time a user gets enrolled in the relevant course. Unassigning a user from a coupon course will not increase the remaining coupon quota.
Please note: Coupons are not interchangeable and there is no way to remove a coupon from a user. Coupons are automatically revoked only in cases where a user that is enrolled in the course and has no completion in it, gets deactivated. Read also: Revoked Coupons Functionality
In the left navigation, make sure you are in the Academy Workspace.
When in the Academy Workspace, select Training Admin.
Select External Courses and then select Categorize Courses.
Here you can see all the coupons within your academy, including their price, quota, and expiration date.