Last updated: 2025-05-06

Sending emails from Opter

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If you use Microsoft 365 as your email service, you must send emails via the Microsoft Graph API. For more information, see Sending emails from Opter using Microsoft 365.

In order to send, for example, notifications and invoices by email from Opter, the email account to be used as the sender must be set up in the office settings.

If you have your own SMTP server, it may not be necessary to create an email account with a username and password (open relay) in some cases. In that case, contact your IT department.

Step 1: Create an email account with your IT provider or on your email service

Contact your IT provider to create an email account that can be used in Opter. If you are running Opter Cloud, you cannot use port 25 because Microsoft has blocked it for outgoing traffic.

Port 587 is usually used for outgoing emails. We also recommend using secure SMTP (SSL).

It is not possible to use two-factor authentication (2FA, MFA) for email accounts that are used by Opter.

Step 2: Configure the email account in Opter

Click on Settings > Offices and go to the Servers tab. Fill in the following fields with the information from the email account:

  • SMTP-server

  • Port

  • Username (usually the email address)

  • Password

  • Secure connection (SSL)

When finished, click on Test email and check the settings by sending a test message to any receiver.

Step 3: Enter the sender's address

Go to the General tab and enter the address of the email account in the Email field. Usually it is the same as the username entered on the Servers tab. This address is used as the sender of emails from Opter. To use a different email address as a sender, see Alternative email addresses.

Troubleshooting

Please contact your IT provider, or log in to the email service you use, and check that the following account settings in Opter (tab Servers) match the email account details:

  • server address (SMTP-server)

  • port for outgoing emails (Port)

  • username/email address of the email account (Username)

  • password for the email account (Password)

  • authentication method (Secure connection (SSL))

Check the settings in Opter by clicking on Settings > Offices and going to the Servers tab. Then click on Test email and check if any error messages are received. They can help the IT provider to find the error.

If you use Microsoft 365, Opter must be registered as an app in Azure. For more information, see Sending emails from Opter using Microsoft 365.

Microsoft has blocked port 25. Since the cloud service is hosted in Microsoft Azure, it is not possible to use port 25 to send emails from Opter Cloud. Change the port for outgoing emails at your email provider and in the office settings (Servers tab), e.g.to 587.

If the email account has an email address other than the one entered on the General and Invoice details tabs in the account settings, the account must have permission to use those addresses as senders. Contact your IT provider, or log in to your email service, to make the settings.

If email messages are sent from an SMTP server other than the one in the domain from which the messages are sent (e.g. “courierservices.com”), the receiving server may interpret the messages as junk mail. Contact your IT provider to add the SMTP server’s IT address as permitted in the DNS settings. For more information, see https://wordtothewise.com/2014/06/authenticating-spf/.

See also