Emails have stopped working from azure web app

Question

Emails have stopped working from azure web app

Suvarna 0

We have hosted our website on the Microsoft Azure platform. We able to send emails since last week, but from yesterday the mails are not reaching the mail server. We have tested it from our local and it is working. However, from the azure site, it is not working getting error like "unable to connect to remote server"

SnehaAgrawal-MSFT 22,706 Reputation points Moderator

2023-12-21T12:47:15.1066667+00:00

@Suvarna Just checking if you have chance to see recent response.

Please let us know if further query or issue remains.

Please accept as "Yes" if the answer provided is useful, so that you can help others in the community looking for remediation for similar issues.
SnehaAgrawal-MSFT 22,706 Reputation points Moderator

2024-01-03T08:21:18.8966667+00:00

@Suvarna There is a possibility that your web app outbound IP is blacklisted in mail servers. Please see this answer as it is relevant to your scenario as well https://stackoverflow.com/questions/58953123/i-can-not-send-email-from-python-azure-function-smtp-office365-com-587/58958407#58958407

We recommend to use authenticated SMTP relay services to send email from Azure VMs or from Azure App Service.

(These relay services typically connect through TCP port 587, but they support other ports.) These services are used to maintain IP and domain reputation to minimize the possibility that external domains reject your messages or put them to the SPAM folder.

SendGrid is one such SMTP relay service, but there are others. You might also have an authenticated SMTP relay service on your on-premises servers.

Using these email delivery services isn't restricted in Azure, regardless of the subscription type.

Let us know if you have further query on this or issue remains.

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SnehaAgrawal-MSFT 22,706 Reputation points Moderator

2023-12-21T12:47:15.1066667+00:00

@Suvarna Just checking if you have chance to see recent response.

Please let us know if further query or issue remains.

Please accept as "Yes" if the answer provided is useful, so that you can help others in the community looking for remediation for similar issues.
SnehaAgrawal-MSFT 22,706 Reputation points Moderator

2024-01-03T08:21:18.8966667+00:00

@Suvarna There is a possibility that your web app outbound IP is blacklisted in mail servers. Please see this answer as it is relevant to your scenario as well https://stackoverflow.com/questions/58953123/i-can-not-send-email-from-python-azure-function-smtp-office365-com-587/58958407#58958407

We recommend to use authenticated SMTP relay services to send email from Azure VMs or from Azure App Service.

(These relay services typically connect through TCP port 587, but they support other ports.) These services are used to maintain IP and domain reputation to minimize the possibility that external domains reject your messages or put them to the SPAM folder.

SendGrid is one such SMTP relay service, but there are others. You might also have an authenticated SMTP relay service on your on-premises servers.

Using these email delivery services isn't restricted in Azure, regardless of the subscription type.

Let us know if you have further query on this or issue remains.

Answer 1

@Suvarna Thanks for reaching here!

You might want to know that to send email from the web application, you need to use a relay service. This is a requirement for all Azure services, including VMs and cloud services. Azure does not allow direct email sending to prevent SPAM abuse. You can use SendGrid, O365, other third-party relay services, or your own on-premises relay service. Please check if you are using a relay service for your email. If not, you must configure your application to use one. see- https://learn.microsoft.com/en-us/azure/virtual-network/troubleshoot-outbound-smtp-connectivity

If already using- try below steps to troubleshoot-

Check if the SMTP server is up and running, try to connect to it using a telnet client. If the connection fails, the SMTP server may be down or there may be a network problem.
See if the SMTP server settings in your web app are correct, verify that the SMTP server address, port number, and credentials match the ones provided by your SMTP service.
If there are any firewall rules or network security groups that block outbound traffic from your web app to the SMTP server, look at the network security group rules for your web app and make sure they allow the SMTP port.
If you are using a third-party SMTP service, make sure that you have configured it correctly and that your web app has permission to use it.

Suggest you to refer this detailed blog on How to fix SMTP problems and send emails from Azure web apps

Let us know, if issue remains.

Suvarna 0 Reputation points

2024-01-02T11:27:44.03+00:00

Hi SnehaAgrawal,

you mentioned relay services to send email but since last month emails working fine in my web app hosted in azure. suddenly stop working in December. so far SMTP server working fine and there is no firewall issue. Please let me know is there any recent changes in azure for email sending?

I was tested my web app from local it working as expected but from azure no email received and getting error like unable to reach email server.

Please help me on this to diagnose the issue

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Emails have stopped working from azure web app

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