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Preview not working - 401 ERROR /passthrough?provider=spo&...
It sounds like you're dealing with a frustrating issue with file previews in SharePoint, specifically encountering a 401 ERROR. Here are some troubleshooting steps that might help resolve the problem:
Check Authentication and Permissions:
Verify Access Permissions: Ensure that the users experiencing issues have the correct permissions for the files and the SharePoint site.
Authentication Tokens: Try clearing your browser’s cache and cookies or refreshing authentication tokens, as expired tokens can sometimes cause access issues.
Review SharePoint Configuration:
Site Collection Features: Confirm that all necessary site collection features related to file previews are activated. Disabled features might lead to preview problems.
Web Part Configuration: If you are using web parts to display file previews, ensure they are correctly configured and not conflicting with other elements on the page.
Investigate Network and Security Settings:
Firewall and Proxy Settings: Check if any network or security configurations, such as firewalls or proxies, might be blocking access to the preview service.
Security Policies: Review recent changes in security policies that could affect preview functionality.
Examine SharePoint Logs:
ULS Logs: Look into SharePoint’s Unified Logging Service (ULS) logs for any errors or warnings related to file previews.
Event Viewer: Check the Event Viewer on the SharePoint server for related errors or warnings.
Check File Types and Sizes:
File Size Limits: Ensure that the file sizes do not exceed SharePoint’s or your organization’s limits.
File Type Support: Verify that the file types you are trying to preview are supported by SharePoint.
Consider SharePoint Updates:
Patch and Update: Ensure that your SharePoint installation is up-to-date with the latest patches and updates.
Test with Different File Formats:
Different File Types: Try previewing various file types and sizes to determine if the issue is specific to certain files.
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If the issue persists, consider reaching out to Microsoft Support for further assistance.
I understand how frustrating it can be when file previews in SharePoint are not functioning as expected, especially with PDF files returning a 401 ERROR when accessing them via /passthrough?provider=spo&.... Since you've already gone through checking permissions and trying different browsers and operating systems, let’s explore some other avenues to troubleshoot this issue.
Double-check Document Permissions: Even if you've reviewed permissions, ensure that the specific PDF files in question are shared correctly with all relevant users. It's possible that individual file settings might differ from the folder settings.
Browser Cache and Cookies: Sometimes, cached data can lead to unexpected behavior. Try clearing the cache and cookies in the browsers you’ve tested to see if that resolves the issue.
File Integrity: Make sure the PDF files are not corrupted. Attempt to download and open the files directly instead of relying on the preview feature to check if they function correctly.
SharePoint Settings Review: Review the SharePoint settings to confirm that the File Viewer feature is enabled. Any adjustments here can significantly impact file preview functionality.
Network Configuration: If your organization uses a VPN or proxy, this could interfere with SharePoint's ability to display previews. Testing the previews on a different network or without a VPN could provide more clarity.
Microsoft Support Assistance: If you continue to experience issues, reaching out to Microsoft Support may be the best course of action. They can provide specific insights and support tailored to your SharePoint setup.
At https://techglitchy.com/, we appreciate the importance of smooth operations in your workflow, and we’re committed to helping you tackle these technical hurdles. If you discover any solutions or need further assistance, please feel free to reach out. Wishing you the best of luck in resolving this issue!