If your account has reached a spending limit, you will receive the error message "You need credits or a valid subscription to use the API" and you will be unable to authenticate with the DataSift API.
If you are a 'Pay-As-You-Go', or Free Trial user, you will receive this message when your balance reaches $0. To resolve this, you will need to log into your DataSift account, and head to datasift.com/billing/payment/details to top up your account using a credit card.
If you pay for a monthly subscription, you will receive this message when you hit your Overall Cost Limit. An explanation of your Cost Limit can be found in our Understanding Billing documentation. To resolve this, you will need to log into your DataSift account, and head to datasift.com/billing to increase your Cost Limit.