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Error 0x80040115

How to Fix Outlook Exchange Server Connection Lost (0x80040115)

Fix time: 10 mins Difficulty: Easy 0 views Updated: July 2026

Troubleshoot Outlook Exchange Server network connection failures and MAPI client issues.

Symptoms

  • Outlook displays "Connection to Microsoft Exchange has been lost"
  • Mailbox sync halts with error 0x80040115

Common Causes

  • Corrupted DNS resolver cache or outdated Outlook MAPI profile settings

Step-by-Step Solutions

Method 1: Flush DNS Cache

  1. Open Command Prompt as Administrator.
  2. Run: ipconfig /flushdns

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Frequently Asked Questions

Yes, enabling Cached Mode helps buffer network fluctuations.