All systems are operational
Maintenance
US IMAP email server downtime

On 22 July 2026 at 10:00 am US/Central time (UTC -5) one of our US IMAP email servers will be shut down for infrastructure maintenance. The server will be offline during the maintenance and the expected downtime is 6 hours.

Affected customers will be notified individually via email.

No incoming mail will be lost while the server is offline. Mail that arrives during the maintenance will be deferred and delivered once the mail server is back online.

We realize that the timing of this relocation is not ideal. If you have business-critical mailboxes and would like them to be available during the maintenance then please email support@opalstack.com or reply to this message to make arrangements to have your mailboxes migrated to a different IMAP server prior to the scheduled maintenance date.

If you have any questions or concerns regarding this maintenance then please email the Opalstack support team for assistance.

Past Incidents

5th January 2022

No incidents reported

4th January 2022

No incidents reported

3rd January 2022

Email: Germany German SMTP blocked by Microsoft

On January 3 2022 at 20:47 UTC Microsoft began blocking mail sent from smtp.de.opalstack.com to domains that use the Microsoft 365 email system.

Microsoft's own IP reputation and junk mail reporting systems indicate that there are no problems with smtp.de.opalstack.com so we've reached out to them for answers.

We'll update this post as soon as more information is available.

In the interim as a possible workaround customers may create a new mailbox on our US mail server and use that temporarily for their outgoing email authentication.

  • It's been over a week and we've seen no blocks of the new server IP by MIcrosoft, so we consider this to be resolved.

  • We informed Microsoft of our findings and the corrective action we've taken but we've still received no further communication from them.

    To work around this we've moved smtp.de.opalstack.com to a new IP address. Customers do not need to change any settings - the DNS change should propagate automatically within the hour.

    After the DNS change has propagated, customers should be able to send mail to email addresses that are hosted by Microsoft.

    We'll leave this incident open and will continue to monitor.

  • We've still not heard from Microsoft but we believe we've identified the activity that triggered the block and are taking action to mitigate it at this time.

    We'll notify Microsoft of the actions we're taking and continue to hold on for a response.

  • We're still awaiting a response from Microsoft and have reached out to them as a reminder.

    • 2nd January 2022

    No incidents reported

    1st January 2022

    No incidents reported

    31st December 2021

    No incidents reported

    30th December 2021

    No incidents reported