Encountering the Outlook Error 503, which states, \”Valid RCPT command must precede DATA,\” may occur during email transmission. This indicates a failure in authenticating your SMTP (outgoing mail) connection by your email server.
The two primary reasons for this issue are:
- Your email server mandates checking emails before sending (a security measure employed by your email provider).
- Your email client lacks proper setup for SMTP Authentication.
To resolve the Outlook Error 503 Valid RCPT command must precede DATA, follow these steps. These instructions are applicable for Outlook 2016, Outlook 2019, and Outlook 365.
Checking email before sending
Your email client checks your inbox first when you first open it. But if, after roughly half an hour, you try to send an email and encounter this notice, just check your inbox for fresh correspondence. If this is the issue, you will then be able to send an email (most often with Outlook).
Most of the time, Outlook Error 503 alerts you to the necessity of configuring SMTP Authentication in your email program.
Setting up SMTP Authentication
Configuring SMTP Authentication in your email client requires you to edit your email account SMTP (outgoing mail) settings. Add your email address and password to the SMTP settings, and you won’t receive any more Outlook Error 503 Valid RCPT command must precede DATA messages.
How you set up SMTP Authentication depends on the email client you use. Here’s how to set it up in Outlook:
- Open Outlook.
- Open the File menu and select Account Settings > Account Settings.
3. In the Account Settings window, select the email account you wish to set up and click Change…
4. In the Change Account window, click More Settings…
5. From the More Settings window, select the Outgoing Server tab.
6. Check My outgoing server (SMTP) requires authentication.
7. Select Use same settings as my incoming mail server.
8. Open the Advanced tab.
9. In the Advanced tab, set the Outgoing server (SMTP) port to 465. In the Use the following type of encryption drop-down, select SSL.
10. Click OK.
11. On the Internet E-Mail Settings window, click Next.
12. Click Finish.
Should you require any assistance with the above, please feel free to contact us.