I think we can practice in both periods. You can do yoga movements with different functions.

In the morning, your brain is awake and alert, but your muscles may be a little stiff. Therefore, practicing in the morning can relax your stiff muscles and prepare your brain and body for the new day.

At night, your body is convenient and more flexible, but your brain may be very tired. Practicing at night can stretch your body well and release the pressure and tension brought by the day.