Why wasn’t my active account credit applied?

The reason why could be because of

1. Time in garage minimum/maximum.
2. Redeemable for express or reservation only.
3. Redeemable only on certain days.
4. Redeemable only if entered garage within specific time frame.

To check your credit restrictions, 

1. Go to account Account Settings 
2. Choose Account Credits
3. Click “See more credit details” 
4. View full restrictions