Maximum Credits Exceeded SendGrid

SendGrid returns Unauthorized (401) Maximum credits exceeded when your account is no longer permitted to send email. The word "credits" is misleading: although SendGrid consumes one credit per email, this error is rarely just "you sent too many emails." It is frequently triggered by a plan downgrade, an unpaid upgrade, or a frozen account — so check your account state before assuming you simply hit a volume limit.

What causes "Maximum credits exceeded" on SendGrid?

Per SendGrid's official explanation, the 401 is raised in several distinct situations:

• Free Trial / end-of-trial limit reached. Email API Free Trial accounts are capped at 100 credits per day. This is a daily limit that resets at midnight UTC — not a monthly one. (The free offering is a 60-day trial, after which an unpaid account behaves as end-of-trial.)
• The account was downgraded. A billing termination, a failed reactivation, or an accidental change can drop a paid account back to a Free Trial / end-of-trial state, which immediately re-imposes the 100/day cap.
• Monthly plan allotment cap hit. As of March 26, 2026, SendGrid applies a hard sending cap to Email API Essentials and Pro plans at 10× the plan allotment per month. For example, an Essentials 50K plan can send up to 500,000 requests in the month before this error fires. Accounts provisioned through resellers have a lower 2.5× cap.
• You upgraded the wrong product. SendGrid bills Email API and Marketing Campaigns separately. Upgrading Marketing Campaigns does not raise your Email API (transactional/SMTP) sending limit.
• Unpaid upgrade or invalid payment. A recent plan upgrade with pending/prorated charges, a declined card, or a frozen account will also surface as this 401.

This is the same condition Twilio surfaces as error 60603 ("SendGrid maximum credits exceeded") when Twilio Verify sends email through a linked SendGrid account.

How do I fix "Maximum credits exceeded"?

1. Confirm your plan is paid and active. In the SendGrid dashboard go to Settings → Account Details → Your Products and verify the Email API plan (not Marketing Campaigns) shows a paid tier. If it shows Free Trial / end-of-trial, your account was downgraded — re-upgrade it.
2. If you're on the Free Trial, wait until the next day (the 100-credit counter resets at 00:00 UTC), or upgrade to a paid Email API plan for higher volume.
3. Check for billing problems. Make sure any recent upgrade's prorated charge was actually paid and your payment method is valid; a declined charge can freeze sending.
4. Check your monthly volume against the cap. Use Stats or the Event Webhook to total your sent requests for the month and compare against your plan's 10× (or 2.5× for resellers) allotment. If you're legitimately near the cap, upgrade the plan.
5. Contact SendGrid support if the account was downgraded unexpectedly or remains blocked after payment.

If you route SendGrid through Courier, this 401 appears in your Courier message logs as a provider error from SendGrid; resolving it on the SendGrid side (plan/billing) clears it for Courier as well. Configuring a backup provider in a Courier routing strategy lets notifications fail over while you resolve the SendGrid limit.