Troubleshooting smtp protocol returned a permanent error 550 5.0.0: Step by Step Guide

This error occurs when the server doesn’t support the protocol, which, in turn, prevents messages from being relayed to the server.
This can prevent you from accessing your favorite email providers, so you need to be careful when trying to resolve smtp protocol returned a permanent error 550 5.0.0.

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    Check your firewall

    1. Most firewalls block ports 25 and 587, which are used by SMTP servers.
    2. Check if your computer is behind a firewall and disable it temporarily or permanently.
      Check if your computer is behind a firewall and disable it temporarily or permanently.
    3. If your firewall blocks ports 25 and 587, then you can try a different port.
    4. Make sure SMTP is not blocked

    Check your antivirus

    1. If you are using an antivirus, turn it off temporarily and check if the issue has been solved.
    2. Check your email provider
      Check your email provider and see if there is a problem with the server.
    3. Check your email provider server settings
      Check your email provider server settings and see if they are correctly configured.

    Check your DNS server

    1. Open Run by pressing the Windows key + R shortcut.
    2. Input †̃cmd’ in Run, and press the Ctrl + Shift + Enter keys simultaneously.
      Input †̃cmd' in Run, and press the Ctrl + Shift + Enter keys simultaneously.
    3. Then type the command †̃ipconfig /flushdns’, and press the Enter key.
    4. Restart Windows after this command runs.
    5. Verify your IP configuration
      Open Run by pressing the Windows key + R shortcut.
    6. Input †̃cmd’ in Run, and press the Ctrl + Shift + Enter keys simultaneously.
      Input †̃cmd' in Run, and press the Ctrl + Shift + Enter keys simultaneously.
    7. Then type the command †̃ipconfig /all’, and press the Enter key.
    8. Restart Windows after this command runs.
    9. Log out of Office 365
    10. Open Run by pressing the Windows key + R shortcut.
      Open Run by pressing the Windows key + R shortcut.
    11. Input †̃cmd’ in Run, and press the Ctrl + Shift + Enter keys simultaneously.
      Input †̃cmd' in Run, and press the Ctrl + Shift + Enter keys simultaneously.
    12. Then type the command †̃net user’, and press the Enter key.
    13. Restart Windows after this command runs.

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  • Check your outgoing SMTP server

    1. Your server may be configured to only allow connections to port 587, and 5.0.0 is its default port.
    2. In that case, users need to configure the SMTP server to use port 25, which is the standard port for sending emails.

    Perform an SMTP port scan

    1. Start the Network and Sharing Center
      Click on Change adapter settings
      Right-click the Local Area Connection and click Properties
      Click on the Internet Protocol Version 4 (TCP/IPv4)
      Click Properties
      Click Advanced.
    2. Click the WINS tab.
    3. Click to clear the WINS checkbox.
    4. Click to clear the LMHOSTS checkbox.
    5. Click OK.
      Click OK.
    6. Restart the WAN Miniport (UPD) service.
      Restart the WAN Miniport (UPD) service.

    Perform an SPF check

    1. Open your email client and click on the “Settings” icon.
    2. Click on “Add new email”.
      Click on
    3. Enter the correct details for the new email account.
    4. Next, click on the “Options” button.
    5. Select the “Enter address manually” option.
    6. Next, click on the “Check My Email” button.
    7. Enter the email address into the “Enter email address” field.
      Enter the email address into the
    8. Select the “Check” option.
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    Check your user account

    1. If your email account is showing smtp protocol returned a permanent error 550 5.0.0, it will be because of your account.
    2. Double check your email account.
      Double check your email account.
    3. Ensure that you are using the right account.
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