If the issue persists, repeat the process and choose Online Repair. This process replaces damaged core files without removing your data or customizations. 21Vianet also expect customer to collaborate at reasonable level accordingly.

⃣ Reset Browser Cookies Cache

21Vianet understands that receiving timely technical support from qualified professionals is a key aspect of cloud services. Equally important is the critical role that the customer’s IT department plays in the support of its users. The Microsoft 365 operated by 21Vianet technical support team troubleshoots only those issues that are related to Microsoft 365 operated by 21Vianet. Incorrect system time can break your connection to Microsoft’s authentication servers. Always enable Set time automatically and select the correct region in your Windows settings.

Microsoft 365 Apps Crashing After Update — Step-by-Step Repair Guide

• If login issues are still persisting, our experts can assist you live via WhatsApp.
• Stay tuned on FixTechGuide.com for more troubleshooting guides and expert fixes.
• Always enable Set time automatically and select the correct region in your Windows settings.
• The Microsoft 365 Copilot app empowers your employees to do their best work with Copilot in the apps they use daily.
• Outlook and Office 365 sync issues can be frustrating but are almost always fixable.

Follow each method step-by-step to ensure smooth performance and protect your work data. Stay tuned on FixTechGuide.com for more troubleshooting guides and expert fixes. The Outlook Login Issues Troubleshooting type of support Microsoft provides for consumers depends on the product you’re calling about and if you have a productfor home or for business use. Anyone in your organization can quickly create documents, presentations, and worksheets within a single, unified app experience. Microsoft 365 Basic now comes with 100GB of cloud storage, secure photo and file storage, secure ad-free email, and technical support. The administrator is expected to provide initial assistance for the customer’s users.

? Fix Office 365 Login Issues on Mobile

If all else fails, uninstall Microsoft 365 completely, remove remaining registry traces using the Office Uninstall Support Tool, and reinstall it fresh. This guarantees clean configuration files and resolves deep-level Outlook Stuck on Synchronizing Folders corruption issues. Partial updates often break compatibility between Windows libraries and Office binaries.

Step 2 – Update Outlook and Office 365

Go to Settings → Windows Update and install all pending updates. Then open any Office app → File → Account → Update Options → Update Now to ensure both are synchronized. Go modern authentication troubleshooting to Control Panel → Programs and Features, select Microsoft 365, and click Change → Quick Repair.





Outlook and Office 365 sync issues can be frustrating but are almost always fixable. Start with basic network checks, enable Cached Exchange Mode, and repair your data files if needed. For persistent problems, rebuild your Outlook profile or use FixTechGuide’s free diagnostic tools to automate detection of authentication and IMAP errors in seconds. The problem usually occurs due to authentication token mismatches, cached credentials, or browser session conflicts. In this guide, we’ll walk you through every step to fix Office 365 login problems on both Windows and the web version. If your Microsoft 365 suite keeps crashing or you can’t recover lost files, reach out for expert help right away.