If you successfully redeemed your promo code but your account still shows as "Roots Free", the subscription status with Apple likely got out of sync. Here's how to fix it:
First, confirm the redemption worked:
Open your iPhone Settings > [Your Name] > Subscriptions > Roots
Check if the promo code subscription is displayed there
If it's listed in Apple Subscriptions:
Go to Roots > Profile > Account Settings (top of the screen) > Your Name > Tap "Restore Subscription" (under "Subscription")
Your premium access should be restored instantly.