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

• Whether it’s Outlook, Word, or Excel, these fixes ensure your data is re-indexed, searchable, and synced properly.
• Alternatively, generate an app-specific password if using Outlook 2016 or older.
• 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.
• Billing and subscription management support can be accessed using the same phone number and online service request process as with technical support.
• 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., online Outlook email repair utility 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 profile repair and recovery steps 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 FixTechGuide Outlook repair tutorial 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.