Problems with sending emails are inconvenient to any user. When an attempt is made to sent mail without authentication, it is possible only if the server is an open relay. However, this is commonly not the case. Therefore, mail sent without the proper SMTP authentication will be rejected by the server. Many iOS device users have experienced receiving the following message when sending emails:

Cannot Send Mail

A copy has been placed in your Outbox.

The recipient was rejected by

the server because it does

not allow relaying”

The emails are being rejected by the server because relaying is prohibited. Relaying is the process of accepting an email and delivering it to non-local email address(es). Prior to the relaying process, the user is required to authenticate. When the process is not executed, error messages pop up.

Some Apple users receive this message after conducting a back up restore. The iPad and iPhone users can also experience this problem when configuring an Apple device for the first time or when software updates are installed.

If Mac users experience the email problem while connected to the Internet, the Internet Provider may be a part of the problem. However, the primary reason why you would receive this error message is because one or more of your email outgoing mail server settings need to be changed. Incorrect mail settings is the most common reason for the problem in iPhones. The configuration may have the wrong server name or incorrect ports.

To fix this problem, changing or resetting the established credentials in your email account settings is recommended.

Open Your Email Account

Open mail account. Go to Settings > Passwords & Accounts. Select your email account. Next, verify your account information.

Check Your Settings

Select ‘Settings’ and go to Mail (iOS 10), Accounts & Passwords (iOS 11), or Passwords & Accounts (iOS 12) depending on your iOS version. Select the problem email address. Make sure the mail toggle is ON. The correct Username and Password must be inputted to send mail from your email account.

You may also check recommended settings for your email account with the Mail Settings Lookup Tool. Enter your email and select ‘Look Up Settings’. Use the tool to verify that the information in your Settings are correct. If any information is inaccurate, enter the correct information manually.

Check Outbox Server SMTP Settings

Oftentimes, the solution to the email error is to re-authenticate and represent the login credentials. Go to Account Information > Outgoing Mail Server SMTP > Primary Server. Select your email address and scroll down to SMTP. Make sure that login credentials are provided for both incoming and outgoing mail on the server.

Select ‘Edit SMTP Server List

Select ‘Edit SMTP Server List’. Re-enter the information for Username and Password fields. Verify that Authentication is set to ‘Password’. Verify that Use SSL is ON. The screenshot shows a prompt to configure gmail through the SMTP2Go server:

The Username is your_smtp_username. The server port is 587. Notice that the secured selection using SSL is not activated. Select ‘Done’ to save the changes. If you experience problems editing the SMTP, turn the Server OFF and then restart.

Review SMTP Relay Options

If the problem persists after updating the credentials in the SMTP server, a more detailed analysis of the SMTP may be required. The SMTP Server must be ON. Go to Administration Program and expand Servers > Localhost > Connectors branch. Right-click the SMTP icon. From the pop-up menu, select Properties > Relay. The Settings should 1. Allow relay for authentic senders; 2. Allow relay for privileged IP ranges; and 3. Allow relay for local sender addresses.

If spammers have discovered your authentication credentials, the MTA and SMTP log sizes may be unusually large, valid emails will be delayed, the Outbox will be filled with unsent emails, and your IP address is blacklisted. In some cases, because the SMTP outbound has so many messages, the Administration program is overloaded and dysfunctions. When this is the case, you should use the command prompt to navigate Mail Enable\Queues\SMTP\Outgoing\Messages. Intrusive activity can be found in the files for that directory.

Emails can be delayed or disabled due to SMTP port blocks. In some cases, the mail server experiences errors in accepting connections to the SMTP port because of configuration errors or firewall settings. The SMTP server can be affected by security conflicts that are caused by the antivirus software or the firewall settings. These elements can be disabled temporarily during a test of the server.

Software bugs can also be the problem

Software bugs can also be the problem. Further, when spammers relay through your server, the SMTP Debug Log may show actions such as:

To address these types of problems, reduce the number of email recipients per hour and require that senders use valid email addresses. Enable Enforce Password Policy and use Check Existing Passwords and enable abuse prevention.

Send a Test Email

Send a test email to make sure the problem has been solved. The unsent messages in your outbox should be sent automatically.

Get Help From Email Service Provider

Several strategies to fix the email relay error have been presented here. However, if none of the suggested remedies restore your email from Authentication failure and other SMTP problems, you can contact your email provider for direction and also to check the email size and SMTP send limits for your email account.

Delete the Email Account and Create New One

If no solution has eliminated the relay error problem, you may consider creating a new email with all the appropriate settings. First, delete the problematic email account. Choose ‘System Preference’ from the Apple menu. Choose ‘Internet Accounts’. Select the problem email from the list. Click ‘-‘ or use the Delete key. Confirm the deletion by clicking ‘Ok’ in the confirmation window:

Create the new email account and send a test email. Once the old email account is replaced, be sure to keep your device updated with the latest software.