Outlook Error Codes

How to Fix Outlook Error AS(8561): Unable to Send or Receive Email

Maira Mehtab Sep 21, 2026 869 views

Question details

The user is unable to send or receive emails in their mail application, which displays the error code AS(8561).

Product: Microsoft Outlook
Device & OS: not provided
Scenario: Attempting to sync, send, or receive messages in the email client.
Observed behavior: The email synchronization fails, halting inbound and outbound messages, and prompts the error AS(8561).

Before you start

Verify that your device is connected to a stable internet network and check the Microsoft Service Health status page to rule out any temporary global server outages.

Solution 1Recommended

Verify Account Credentials and Mail Server Settings

Incorrect server configurations or outdated passwords are the most common causes of synchronization errors like AS(8561).

Email providers frequently update security protocols or require app-specific passwords. Ensuring your server ports and authentication methods are correct is the fastest way to restore your connection.

Open Account Settings

Launch Outlook, click on 'File' in the top left corner, then select 'Account Settings' and click 'Account Settings' again from the dropdown.

Access Server Settings

Select the email account experiencing the error and click 'Repair' or 'Change' to view your incoming and outgoing server details.

Update Credentials and Ports

Ensure your password is up to date. Click 'More Settings' > 'Advanced' to verify the correct port numbers (such as 993 for IMAP and 465 or 587 for SMTP) are configured according to your email provider's requirements, then save your changes.

App-Specific Passwords: If you use two-factor authentication (2FA) with providers like Gmail or Yahoo, you may need to generate an app-specific password to use in Outlook instead of your standard account password.

Solution 2

Clear the Outbox and Restart Outlook

A corrupted or overly large email stuck in the Outbox can block all other send and receive processes.

Solution 3

Create a New Mail Profile

Recreating your mail profile can resolve deep-seated corruption issues that standard repairs cannot fix.

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Frequently Asked Questions

What does error AS(8561) indicate in Outlook?

Error AS(8561) generally indicates a synchronization failure where the mail application cannot successfully authenticate or communicate with the email server. This is often caused by outdated passwords, incorrect port settings, or temporary server outages.

Can third-party antivirus software cause Outlook send/receive errors?

Yes. Overly strict antivirus or firewall settings can sometimes block the specific network ports (like 993, 995, or 465) that Outlook uses to send and receive emails. Temporarily disabling the email scanning feature in your antivirus can help determine if it is the cause.

How do I know if the issue is with my account or the Microsoft server?

You can isolate the issue by logging into your email account via a web browser (webmail). If you can successfully send and receive emails in the browser, the issue is likely with your Outlook application configuration. If webmail also fails, there may be an account suspension or a server-side outage.

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