However, if the administrator is unable to resolve issues with the help of self-service support resources, they should Contact support. Technical support for Microsoft 365 operated by 21Vianet subscriptions provides assistance with basic installation, setup, and general technical usage. If you’re a volume licensing admin but are unable to access the admin center, you can create an online support request. With every subscription of Microsoft 365 operated by 21Vianet, 21Vianet support provides technical, presales, billing, and subscription support. Have your Microsoft 365 apps suddenly started crashing after a recent Windows or Office update? Many users experience random application freezes, launch errors, and constant crashes after installing new patches or cumulative updates.

⃣ 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.
• When Office 365 search stops working after updates, it’s usually a minor indexing or cache issue — not a major fault.
• 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.
• Then open any Office app → File → Account → Update Options → Update Now to ensure both are synchronized.
• In this guide, we’ll walk you through every step to fix Office 365 login problems on both Windows and the web version.
• Outlook and Office 365 sync issues can be frustrating but are almost always fixable.
• Download the tool from Microsoft and run the Outlook diagnostic to auto-detect server and account issues.

For iPhone users, reinstalling Outlook or updating to the latest iOS often resolves stuck sign-in loops instantly. Many users have both personal Microsoft accounts (e.g., flush DNS and re-sync Outlook Outlook.com) and work/school Office 365 accounts. If both are signed in simultaneously, the system can confuse the authentication path.

? 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 expert Outlook tips by FixTechGuide 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.