Managing cloud infrastructure on Amazon Web Services (AWS) is a common practice for startups and developers due to its powerful tools and flexible pricing model. One of the primary draws for new users is the AWS Free Tier, offering limited usage of various services — including Amazon SES (Simple Email Service) — at no cost. However, this entry-level service comes with boundaries and expiration dates that, if missed, can result in unexpected service interruptions. Having faced this exact issue, I want to share how the termination of my Free Tier led to the suspension of my SES email sending capabilities and break down the steps I took to migrate to a paid version to restore email deliverability.
TLDR
After my AWS Free Tier expired, Amazon SES stopped operating without warning because it was still in sandbox mode and associated with usage constraints. This meant that all email delivery failed until I realized the source of the issue. Migrating to a fully paid AWS account and requesting SES production access resolved the problem and restored sending abilities. This article outlines the warning signs to watch for, what went wrong, and how to effectively recover your SES configuration without interrupting your email communications.
Understanding the Problem: SES in Sandbox Mode
AWS SES starts in *sandbox* mode by default, where sending emails is heavily restricted. You are only allowed to send emails to verified addresses, and there are low sending limits appropriate for testing. When I signed up under AWS Free Tier, SES remained in sandbox mode, per AWS policy. Since I was within the Free Tier usage limit, everything worked fine initially during testing and low-volume use.
However, once the Free Tier period ended, many AWS features remained available — but SES restrictions persist unless explicitly transitioned to production mode by submitting a request. What I didn’t realize was that my SES instance was never upgraded. When AWS started enforcing actual billing, SES simultaneously enforced stricter policies, unexpectedly halting all email delivery.
Immediate Symptoms of the Problem
- Email delivery suddenly failed across all recipients, with low-level bounce errors.
- AWS CloudWatch metrics for SES showed no successful sends or delivery attempts.
- No forward warning was received from AWS that delivery would be impacted upon Free Tier expiration.
After hours of backtracking through server logs and email configurations, I confirmed that the emails were making it to SES, but were silently being blocked due to sandbox restrictions. What confused matters further was the lack of any proactive notification from the AWS console. Amazon treats sandboxed SES as a safety feature, and it doesn’t automatically transition when billing starts. This is both a security and spam prevention measure, but in my case, it caused a mission-critical outage.
Investigating and Confirming the Root Cause
Digging deeper, I began exploring the SES configuration via the AWS Console. Under the SES dashboard, I found this telling message under Account Details:
Your account is in the Amazon SES sandbox. You can only send email to verified addresses and domains.
This explained the issue. Despite my AWS account now generating billing, SES hadn’t exited the sandbox. I wrongly assumed that because payment was now being processed, all services would automatically lift unused constraints. Unfortunately, SES doesn’t operate that way — you must submit a formal request to move out of the sandbox, which involves a short review process by Amazon’s team.
Checklist for SES Troubleshooting (Post Free Tier)
- Verify SES account status: Is it still in sandbox mode?
- Check verified identities: Are you trying to send emails to unverified domains?
- Review CloudWatch metrics: Are messages being throttled or bounced immediately?
- Ensure IAM permissions haven’t changed post-billing activation.
With the root cause clearly identified, it was time to start the migration to a “production” SES setup, which restored sending capabilities and removed volume restrictions.
Step-by-Step: Migrating SES to a Paid Production Setup
Transitioning out of sandbox mode is a straightforward but manual process. Here’s how I handled the upgrade:
1. Apply for Production Access
Go to the SES console and click on “Request production access.” You’ll be prompted to select:
- Mail type (e.g., transactional, marketing, notifications, etc.)
- The expected number of monthly emails
- Information about your use case and anti-spam policies
Amazon reviews this information to ensure your use of SES aligns with its policies and won’t lead to spam or abuse reporting. It can take 24 to 48 hours for your request to be processed, though mine was approved in less than a day.
2. Verify Sending Domains
Before SES lets you send emails at scale, all sender domains need to be verified. This involves adding DNS TXT or CNAME records provided by Amazon into your domain’s DNS settings (typically set via Route 53 or your domain registrar).
3. Request Quota Increase (If Required)
Even after receiving production access, new accounts might still have limits (e.g., 50,000 emails per day). If your use case requires more, apply for a quota increase from the same area in the SES console.
4. Test with Production Recipients
Once approved and verified, SES allows delivery to unverified recipients. I tested my transactional flows (e.g., password resets, confirmation emails, and alerts) and saw deliverability improvements immediately.
Lessons Learned
Reflecting on this event, the disruption could have been avoided with better awareness and proactive migration. Here are the takeaways I want to share:
- Monitor Service Transitions: Don’t assume AWS services scale automatically after Free Tier usage; investigate when upgrades or manual approvals are needed.
- Audit Services Regularly: After any billing change, validate that mission-critical services (like SES) haven’t reverted to restricted modes.
- Use Alarms and Logging: CloudWatch alerts for soft bounces, zero delivery rates, and sending quota warnings can provide early warnings.
- Document Console Notices: Amazon buries important service limits across console pages — keep a configuration checklist after setup.
Conclusion
The sudden failure of my email system tied to SES wasn’t due to a server misconfiguration or API issue — it stemmed from a misunderstood Free Tier transition process on AWS. While AWS remains a robust platform, its many services don’t always signal breaking points clearly. Moving out of SES sandbox mode, verifying sender identities, and responsibly transitioning to a production-grade configuration resolved all issues.
For developers and infrastructure managers relying on cloud services, especially for things as sensitive as email delivery, it’s essential to treat tier transitions the same way you treat application upgrades: with audits, testing, and strong documentation. Don’t let a billing milestone quietly break your services.
If you’re using SES under Free Tier now, it may be time to plan your migration before you hit the wall I did.