We can help you find a solution or connect you to technical support. This restores missing or corrupted Office components that affect search indexing. If a Microsoft 365 application such as Word or Excel isn't working correctly, sometimes restarting it will fix the problem. Download the tool from Microsoft and run the Outlook diagnostic to auto-detect server and account issues.

⃣ 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

• Go to Control Panel → Programs and Features, select Microsoft 365, and click Change → Quick Repair.
• Incorrect system time can break your connection to Microsoft’s authentication servers.
• This restores missing or corrupted Office components that affect search indexing.
• We’ll walk you through step-by-step solutions for Office, Outlook, or Teams sign-in errors.
• Explore learning tools to collaborate on projects together and independently, all in one place.

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., fix Outlook after Windows update issues 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

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 FixTechGuide support for Office 365 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 modern authentication troubleshooting 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.