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 all else fails, uninstall Microsoft 365 completely, remove remaining registry traces using the Office Uninstall Support Tool, and reinstall it fresh.
• Go to Settings → Windows Update and install all pending updates.
• Start with basic network checks, enable Cached Exchange Mode, and repair your data files if needed.
• Support is available both online through the Microsoft 365 operated by 21Vianet portal, and by telephone for both paid and trial subscriptions.
• For iPhone users, reinstalling Outlook or updating to the latest iOS often resolves stuck sign-in loops instantly.
• 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 support telephone number can be found on the Microsoft 365 operated by 21Vianet portal.
• In this guide, you’ll learn how to fix Office 365 search not working after update using step-by-step methods verified to restore indexing and search functionality.

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., credential Loop In microsoft 365 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

It automatically diagnoses and repairs solve Office 365 mailbox sync delays many Office 365 problems — including search indexing and sync issues. In this guide, you’ll learn how to fix Office 365 search not working after update using step-by-step methods verified to restore indexing and search functionality. Whether it’s Outlook, Word, or Excel, these fixes ensure your data is re-indexed, searchable, and synced properly. For more self-help resources, see Microsoft 365 operated by 21Vianet. You must be an admin for a business subscription to use these support methods.

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 FixTechGuide login issue guide 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.