Digital Ocean Promo issue

When I first logged in to Docker cloud about an hour ago, I got a chat from the team indicating a $20 promo code for DigitalOcean cloud hosting service. However, from the cloud settings the generated promo code when entered during signed up for a new DigitalOcean account deems as invalid. Is there any way to fix this??
Since my free tier for AWS has expired and the other services free tier are only 1-3 months max, which is a good option for long term usage that does not cost too much.