Azure Communication Services
An Azure communication platform for deploying applications across devices and platforms.
1,251 questions
Azure Communication Service (ACS) report on mailfrom failures in Azure (rather than application consuming it)
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Andrew Bell
20
Reputation points
As part of using the ACS service we are looking to provision multiple different ACS resources so that each application has its own configuration. One of the questions we have is if an application tries to send from an address that is not registered as an address it (obviously) throws up an SMTP error on the application. However not all applications will handle this gracefully so is it logged anywhere within Azure? I did try within Diagnostic settings to tick every single box (including metrics traffic) and when I generate an SMTP email from a bad address I can see it failing in PowerShell but not a single error is shown anywhere in the logs.
Azure Communication Services
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Shree Hima Bindu Maganti 5,165 Reputation points Microsoft External Staff Moderator2025-07-07T13:48:40.15+00:00 Hi @Andrew Bell
Azure Communication Services (ACS) does not specifically indicate that SMTP errors from sending with unregistered addresses are logged in the current context. Although you can turn on various diagnostic settings to collect logs, it seems that certain SMTP errors may not appear in the logs you are reviewing. The available logs typically include operational logs for email send requests and delivery status, but they might not capture every error, especially those involving sender address validation issues.To capture the necessary logs, consider checking which log categories you have enabled and make sure they include all relevant operational logs for email sending.
References:
- Email SMTP support in Azure Communication Services
- https://learn.microsoft.com/en-us/azure/communication-services/concepts/analytics/logs/email-logs
Are you using a custom domain, or are you sending emails from the Azure-managed domain?
Let me know if you have any further assistances needed.
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Andrew Bell 20 Reputation points
2025-07-07T14:04:17.7533333+00:00 Hi thanks for answer - I have already enabled every single setting possible as can be seen from attached and in checking tables there is not much in the time period. I can see the SMTP authentication (IssueSmtpAccessTokens) occurring, nothing in SendMailOperational or EmailStatusUpdateOperational or any other table in that time period. It looks like this is not logged which is a miss as I would expect it in the EmailStatusUpdateOperational log
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Shree Hima Bindu Maganti 5,165 Reputation points Microsoft External Staff Moderator
2025-07-10T17:55:53.8466667+00:00 Hi @Andrew Bell
Apology for your inconvenience
It appears you're having trouble withmailfromfailures not being recorded in the Azure Communication Services (ACS) logs, particularly in theEmailStatusUpdateOperationallog. This log is intended to show message and recipient level delivery status updates for Email service send mail requests. If you don't see entries for a given period, those failures might not be logged as expected.Please make sure the diagnostic settings for logging are correctly enabled. Check that both Email Service Send Mail logs and Email Service Delivery Status Update Logs are set up to capture the needed information.
If the failures involve SMTP authentication, they might not show up in the operational logs you're reviewing. Double-check your diagnostic settings to confirm all relevant log categories are enabled.
References:
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