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How to Fix Synology NAS WebDAV Authentication Problems in Microsoft 365

WPS Content Manager Oct 8, 2026 868 views

Question details

The user needs to resolve an issue where Microsoft 365 applications reject WebDAV authentication attempts from a Synology NAS.

Resolving Synology NAS WebDAV Authentication Errors in Microsoft 365

Product: Microsoft 365, Synology NAS
Device & OS: not provided
Scenario: Attempting to access, edit, or save files stored on a Synology NAS using Microsoft 365 applications over a WebDAV connection.
Observed behavior: Microsoft 365 rejects the WebDAV authentication method. Modifying Trusted Locations fails to fix the issue, and reverting to older Office versions introduces severe security and compliance risks.

Before you start

Ensure your Synology NAS DSM firmware is fully updated and that you have administrative access to both your Microsoft 365 tenant and the NAS configuration interface.

Solution 1Recommended

Escalate to Specialized Microsoft Q&A and Synology Support

Because this issue involves advanced network configuration, NAS compatibility, and Microsoft 365 security policies, standard community troubleshooting is insufficient. You must seek specialized guidance.

Standard Microsoft Community forums only provide basic troubleshooting for standard Office, OneDrive, and Outlook problems. WebDAV routing and Synology authentication require enterprise-level support channels.

Log into Microsoft Q&A

Navigate to the official Microsoft Q&A platform using your Microsoft 365 organizational account.

Submit a detailed support query

Post your question using the Microsoft 365 and Windows Server tags. Include your Synology NAS model, DSM version, and the specific authentication error codes you are receiving.

Open a Synology support ticket

Log into your Synology Account dashboard and submit a technical support ticket regarding WebDAV compatibility with the latest Microsoft 365 updates.

Escalate to Specialized Microsoft Q&A and Synology Support

Avoid Downgrading Microsoft Office: Do not downgrade your Office applications as a workaround. Running outdated versions of Microsoft 365 creates significant security vulnerabilities and violates organizational compliance policies.

Free Microsoft Office alternative

Try WPS Office for Seamless File Management

If Microsoft 365's strict network security updates disrupt your workflow with your Synology NAS, WPS Office serves as a highly compatible, free alternative. It provides a familiar interface without the aggressive network authentication blocks, allowing you to access your files smoothly.

1. Download the Installer: Visit the official WPS Office website and click the free download button for your operating system.
2. Install WPS Office: Run the downloaded installation file and follow the simple on-screen instructions to set up the software.
3. Access Network Files: Open WPS Office, navigate to your network locations, and seamlessly open documents stored on your Synology NAS.

Highly compatible with Microsoft Office formats (.docx, .xlsx, .pptx)Lightweight software that consumes fewer system resourcesAvoids the complex WebDAV authentication barriers found in Microsoft 365Completely free to use with a familiar, intuitive user interface

microsoft office alternative - wps office

Frequently Asked Questions

Does adding the Synology NAS to Microsoft 365 Trusted Locations fix WebDAV errors?

In most recent cases, adding the NAS IP address or hostname to Trusted Locations does not resolve WebDAV authentication rejections, as the block is enforced by deeper Microsoft 365 security and authentication policies.

Is it safe to downgrade Microsoft Office to restore WebDAV functionality?

No, downgrading is strongly discouraged. Using older versions of Microsoft 365 removes critical security patches, creating significant security vulnerabilities and compliance risks for your organization.

Why can't the Microsoft Community forums resolve this WebDAV issue?

The standard Microsoft Community is designed for consumer-level troubleshooting. Complex issues involving Synology NAS network configurations, WebDAV protocols, and enterprise Microsoft 365 compatibility require the specialized engineers found on Microsoft Q&A and official Synology support.

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