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

Support is available both online through the Microsoft 365 operated by 21Vianet portal, and by telephone for both paid and trial subscriptions. The Microsoft 365 Copilot app brings together your favorite apps in one intuitive platform that keeps your data secure with enterprise data protection. With Microsoft 365, you can designate several types of administrators who serve different functions. This service description uses the generic title administrator to refer to all categories of administrators.

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.
• Then open any Office app → File → Account → Update Options → Update Now to ensure both are synchronized.
• 2 Severity A is only available to customers who signed an advanced online service agreement with 21Vianet through a sales account manager.
• Outlook and Office 365 sync issues can be frustrating but are almost always fixable.

Assistance for billing and subscription management issues is available online or by telephone during China business hours (Beijing Time), Monday through Friday. Billing and subscription management support can be accessed using the same phone number and online service request process as with technical support. The support telephone number can be found on the FixTechGuide support for Office 365 Microsoft 365 operated by 21Vianet portal. 2 Severity A is only available to customers who signed an advanced online service agreement with 21Vianet through a sales account manager. Download and run the official Microsoft Support and Recovery Assistant (SaRA).

? 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 Exchange connectivity diagnostic 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 inbox repair tool alternative to Control Panel → Programs and Features, select Microsoft 365, and click Change → Quick Repair.

Repair Outlook OST File Not Working in Office 365 – Complete Fix (

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.