Exchange Connection Problems

How to Fix Cannot Add Microsoft 365 Mailbox to Foxmail

Maira Mehtab Sep 27, 2026 870 views

Question details

The user is unable to add or connect a Microsoft 365 email account to the Foxmail desktop client, often resulting in password rejections or connection failures.

Product: Microsoft 365 / Foxmail
Device & OS: not provided
Scenario: Attempting to add a Microsoft 365 commercial or personal email account to Foxmail for sending and receiving emails.
Observed behavior: Foxmail rejects the correct password or fails to connect. This happens when modern authentication is required, basic authentication is blocked, or IMAP/POP/SMTP access is disabled by the organization.

Before you start

Before configuring your email, contact your Microsoft 365 administrator to confirm that IMAP, POP, or SMTP protocols are enabled for your mailbox and check if Modern Authentication (OAuth2) is enforced.

Solution 1Recommended

Configure the Correct IMAP and SMTP Settings Manually

Enter the exact server addresses and port numbers required by Microsoft 365 to establish a secure connection with Foxmail.

Microsoft 365 requires specific ports and encryption methods for incoming and outgoing servers. Incorrect settings will result in connection timeouts or rejected credentials.

Open Manual Setup

Launch Foxmail, go to the Account Settings menu, select 'Add Account', and choose the manual configuration option for IMAP or POP.

Enter IMAP Settings

Set the incoming mail server to outlook.office365.com. Change the port to 993 and ensure that the 'SSL' connection option is checked.

Enter POP Settings (Alternative to IMAP)

If you prefer using POP, set the incoming mail server to outlook.office365.com, change the port to 995, and enable the 'SSL' connection option.

Configure SMTP Settings

Set the outgoing mail server (SMTP) to smtp.office365.com. Change the port to 587 and select 'STARTTLS' (or TLS) as the encrypted connection type.

Save and Test

Enter your full Microsoft 365 email address and password, click 'Create' or 'Save', and wait for Foxmail to verify the server connection.

Admin Configuration Required: If the correct settings still fail, your IT administrator may have disabled IMAP or POP access for your specific account.

Solution 2

Use an App Password for Multifactor Authentication (MFA)

Generate a dedicated app password if your organization enforces MFA but still allows basic authentication.

Solution 3

Ensure Foxmail Supports Modern Authentication (OAuth2)

Update Foxmail or authenticate via the modern Microsoft web prompt, as basic authentication is heavily deprecated by Microsoft.

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Frequently Asked Questions

Why does Foxmail reject my correct Microsoft 365 password?

This usually happens because Microsoft requires Modern Authentication (OAuth2) or your organization has enabled Multifactor Authentication (MFA). If your Foxmail client attempts to use basic authentication, the correct standard password will still be rejected.

What are the correct IMAP port settings for Microsoft 365?

The incoming IMAP server is outlook.office365.com. It requires Port 993 with an SSL encryption connection.

Can I still use basic authentication with Microsoft 365?

Generally, no. Microsoft has deprecated basic authentication for Exchange Online for most tenants to improve security. You must use an email client that supports OAuth2 or consult your IT administrator to check if an exception or app password policy is in place.

What should I do if my App Password doesn't work in Foxmail?

If an app password fails, it means your organization's IT policy has completely blocked basic authentication or disabled app passwords entirely. In this case, you must connect using Modern Authentication (OAuth2).

Outlook & Email Problems