SOLVED: Two Easy Fixes for Microsoft Error 657rx 1200 or 0x8004dec5

If you have tried to log into Microsoft Outlook, Teams, OneDrive or other M365 product and see any of these errors, we have the fix:

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Microsoft Error 657rx 1200 or 0x8004dec5

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What Are 657rx, 1200, & 0x8004dec5 Errors

Microsoft errors 657rx, 1200, and 0x8004dec5 are all related to authentication and account issues within Microsoft 365 applications like Outlook and OneDrive. These errors often appear together or are are least resolved by the same troubleshooting steps, as they stem from a few common problems:

Common Causes of Microsoft Authentication Problems

There are three common causes of 657rx, 1200, & 0x8004dec5 errors:

1. Corrupted Credentials: Cached login information, tokens, and certificates on your device can become outdated or corrupted, preventing the applications from verifying your identity
2. Device Trust Issues: The errors can occur if your device’s trust relationship with your Microsoft account is broken. This can happen after a hardware change (like a new motherboard), a major Windows update, or if the device is not properly registered with a work or school account
3. Conditional Access Policies: In a corporate environment, these errors can be caused by security policies that restrict access from specific locations, devices, or network configurations (like, VPNs or proxies)

The Fix!

There are two common fixes for these problems but the first is super easy and solves the problem 90% of the time:

1 – Disconnect / Reconnect your Work and School Account:

1. Go to Settings > Accounts > Access Work or School
2. Select the account that was having problems and click Disconnect
3. Restart your computer then try to sign into whatever was erroring out before

2 – Clear Cached Credentials:

Deleting cached login information from Windows Credential Manager or from specific application folders (like the IdentityCache or OneAuth folders).

2a – To Clear Creds From Credential Manager:

1. Click the Start button, type Credential Manager and select the app from the search results
2. Click the Windows Credentials tab (along the top)
3. Delete any MS 365 / Office related Entries:
   • Look for any entries related to Microsoft Office, Office 365, Outlook, or your specific work/school account
   • Common names to look for include:
     • MicrosoftOffice16_Data:live:cid:xxxx
     • MicrosoftOffice16_Data:orgid:xxxx
     • Entries with your email address or a domain name followed by _Data
   • Click on the entry to expand it and then click Remove
4. Restart your computer and try to sign into whatever was failing previously.

2b – To Clear Creds From IdentityCache and OneAuth Folders

Use File Explorer (aka My Computer), to get to %localappdata%\Microsoft and delete folders IdentityCache and OneAuth. Then restart your computer and try to sign into whatever was failing previously.

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The Wrap

Dealing with credential issues is a frustrating and common source of pain for users. It’s an annoying loop of being told you can’t access something, despite knowing your password is correct.

These problems often stem from hidden, corrupted files and settings that are not easily visible or accessible, creating a difficult and time-consuming troubleshooting process. This can be especially painful when you need urgent access to important documents or communications, turning a simple task into a major headache and productivity roadblock.

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