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

If your admin enabled Modern Authentication (MFA), try disabling it temporarily via Azure Active Directory → Properties. Alternatively, generate an app-specific password if using Outlook 2016 or older. This resets your authentication cache and forces a fresh token request.

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

• Anyone in your organization can quickly create documents, presentations, and worksheets within a single, unified app experience.
• 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.
• This resets your authentication cache and forces a fresh token request.

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 fix MFA prompts not working 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

21Vianet assigns a severity level to a case when it’s opened, based on an assessment of the issue type and customer impact. Examples of issue types and severity levels are shown in the following table. Authorized administrators can use the Microsoft 365 operated reset cached Exchange mode by 21Vianet portal to submit service requests online and access support telephone numbers.

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 Office 365 sync problems and login fixes 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 (

Explore learning tools to collaborate on projects together and independently, all in one place. Create equitable learning environments that help students develop knowledge with familiar apps essential to both academic and future career success. If login issues are still persisting, our experts can assist you live via WhatsApp. We’ll walk you through step-by-step solutions for Office, Outlook, or Teams sign-in errors.