Shared accounts cannot purchase the Xiaomi Home Secure, and only the main account can purchase it.
Here is more information about the subscription to Xiaomi Home Secure:
1. The Xiaomi Home Secure is tied individually to each Xiaomi account. If you have purchased the Xiaomi Home Secure for a camera and then switched to a different Xiaomi account, the Xiaomi Home Secure cannot be used (You will be prompted to repurchase). But if only the phone is replaced, it does not affect the use of the service.
2. No refunds are available after purchasing the Xiaomi Home Secure. It also does not support changing the subscription plan during its active period.
3. You cannot purchase a new service while an existing subscription is active or still in effect.