SharePoint Document Issues

How to Fix Excel SharePoint Connection Reset Error on Internal Networks

WPS Editor Oct 8, 2026 870 views

Question details

Users encounter a connection reset error when attempting to open Excel files hosted on SharePoint Online, specifically while connected to an internal corporate network.

How to Fix Excel SharePoint Connection Reset Error on Internal Networks

Product: Microsoft Excel, SharePoint Online
Device & OS: not provided
Scenario: Opening cloud-hosted Excel files from SharePoint Online over an internal network environment.
Observed behavior: Excel files fail to open and display a connection reset error, whereas Word files open normally from the same SharePoint location.

Before you start

Verify whether this issue happens on all devices connected to the internal network or just yours, and confirm that your internet connection is otherwise stable.

Solution 1Recommended

Consult Your IT Admin for Firewall and Proxy Rules

Since the issue only occurs on the internal network, network security appliances like firewalls or proxy servers are likely blocking the specific endpoints Excel uses to connect to SharePoint Online.

Microsoft 365 services, including Excel and SharePoint, require specific network ports and IP addresses to be whitelisted for proper synchronization. Even if Word works, Excel might attempt to connect through a blocked endpoint.

Contact your network administrator

Reach out to your IT support or network administration team and report the connection reset error occurring only with Excel files on SharePoint.

Request an endpoint review

Ask the administrator to review the firewall and proxy rules against the official Microsoft 365 endpoint guidance to ensure no required connections are being dropped.

Test on a different network

Temporarily connect your device to an external network, such as a mobile hotspot, and attempt to open the Excel file. If it opens successfully, inform your IT team so they can isolate the internal network configuration.

Consult Your IT Admin for Firewall and Proxy Rules

Microsoft 365 Endpoint Guidance: IT administrators can find the required URLs and IP address ranges in the official Microsoft 365 Enterprise documentation for managing Office 365 endpoints.

Solution 2

Inspect Network Traffic with Edge Developer Tools

Use Microsoft Edge's built-in developer tools to capture the exact network request that is failing, providing valuable diagnostic information for your IT team.

Free Microsoft Office alternative

Use WPS Office for Seamless Spreadsheet Management

If network errors and strict internal proxy configurations are preventing you from managing your data effectively, consider trying WPS Office. It provides a lightweight, highly compatible alternative to Microsoft Office, allowing you to edit local and cloud spreadsheets without relying on complex internal network routing.

1. Download WPS Office: Visit the official WPS website and download the free installation package for your operating system.
2. Install the software: Run the installer and follow the quick on-screen instructions to set up WPS Office on your device.
3. Open your spreadsheets seamlessly: Launch WPS Spreadsheets to easily open, edit, and save your .xlsx files locally or to your preferred cloud storage without connection resets.

Fully compatible with Microsoft Excel (.xlsx, .xls) formatsLightweight installation with powerful offline editing capabilitiesBuilt-in cloud collaboration features without complex proxy requirementsFree to use with a familiar, easy-to-learn interface

microsoft office alternative - wps office

Frequently Asked Questions

Why do Word files open from SharePoint but Excel files get a connection reset error?

Different Office applications sometimes utilize different backend endpoints, APIs, or network protocols to sync with SharePoint Online. A strict firewall might inadvertently block the specific required endpoints that Excel relies on while allowing Word's traffic.

Can an internal proxy server cause SharePoint connection errors in Excel?

Yes. If a proxy server intercepts network traffic and lacks the correct bypass rules or exceptions for Microsoft 365 URLs, it can abruptly terminate or reset the connection when Excel tries to authenticate or download the spreadsheet.

How do I quickly test if my internal network is causing the Excel issue?

Try disconnecting your computer from the corporate internal network and connect to a mobile hotspot or an external Wi-Fi network. If the Excel file opens from SharePoint successfully on the external network, the issue is confirmed to be isolated to your internal network's configuration.

Document & File Issues