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

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

• With Microsoft 365, you can designate several types of administrators who serve different functions.
• Many users have both personal Microsoft accounts (e.g., Outlook.com) and work/school Office 365 accounts.
• If your country/region isn’t listed, select a neighboring country/region or dial the United States support phone number.
• This process replaces damaged core files without removing your data or customizations.
• You must have at least one subscription bought through Microsoft to access Microsoft support.
• Microsoft 365 Basic now comes with 100GB of cloud storage, secure photo and file storage, secure ad-free email, and technical support.

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 Outlook Login Issues Troubleshooting 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 Office 365 Sync Errors Fix 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 Outlook OST vs PST repair 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 (

Microsoft 365 with Microsoft Teams helps deliver a complete, secure solution to help everyone work better, smarter, and more cohesively. Microsoft Create has professionally designed, fully customizable templates to help you get things done. Find solutions to common problems or get help from a support agent.