TES - Maintenance
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To keep our platform secure and running optimally, we perform scheduled maintenance on the Transactional Email Service (TES). This page explains what to expect during maintenance periods and how to stay informed.
Types of maintenance
TES maintenance typically includes:
- System updates - Installing critical security patches and platform improvements
- Infrastructure upgrades - Updating underlying hardware and network components
- Service optimizations - Performance improvements and feature deployments
Maintenance schedule
Maintenance is scheduled during off-peak hours to minimize impact on your email sending. We aim to:
- Perform maintenance during low-traffic periods (typically between 00:00 and 04:00 CET)
- Minimize downtime through rolling updates where possible
- Complete most maintenance within 4 hours
Impact on your service
During scheduled maintenance you may experience:
- Brief interruptions in email sending capabilities during system updates and server restarts
- Temporary queueing - Emails submitted during maintenance are queued and delivered automatically after completion
- API response delays - Email API endpoints may respond slower than usual
Our engineers make every effort to minimize service impact and ensure reliable email delivery.
Staying informed
Status page
All scheduled maintenance is announced on our status page:
Subscribe to updates to receive automatic notifications about:
- Scheduled maintenance announcements
- Maintenance progress updates
- Completion confirmations
Maintenance notifications
Status page updates follow a standard format:
- Scheduled - Advance notice with date, time, duration, and expected impact
- In progress - Confirmation when maintenance begins with real-time updates
- Completed - Final update confirming successful completion
Example notification
Scheduled Maintenance: Transactional Email Service
Overview:
Scheduled maintenance for system updates and critical security updates.
Scheduled Time:
Thursday, 08 January 2026, between 00:15 and 04:15 CET
Duration: Up to 4 hours
Impact:
- Brief interruptions in email sending capabilities
- Emails may be queued and delivered after completion
Action Required:
No action required. We recommend verifying critical processes after maintenance.
Emergency maintenance
In rare cases, emergency maintenance may be required to address critical security vulnerabilities or service issues. Emergency maintenance:
- May occur outside scheduled windows
- Will be communicated as quickly as possible via the status page
- Follows the same impact mitigation procedures as scheduled maintenance
After maintenance
After maintenance completion:
- Verify service - Test your critical email sending processes to confirm everything operates correctly
- Check queued emails - Any emails queued during maintenance are delivered automatically
- Review performance - Monitor your email delivery metrics for the next 24 hours
Questions or issues
If you experience any issues during or after maintenance:
- Check the status page first for the latest updates at status.cyso.cloud
- Contact support at support@cyso.cloud
- Include details about specific errors or delivery problems you're experiencing
Our support team is available to assist you with any maintenance-related concerns.