How to Fix Outlook Error 0x80070057

When setting up a new email account or synchronizing your inbox in Microsoft Outlook, you may receive the error: “An unknown error occurred, a parameter was incorrect. Error code: 0x80070057” or “The parameter is incorrect.”

This guide provides details on what triggers error code 0x80070057 and details how to fix it on both Windows and macOS by modifying the system registry, resolving Autodiscover server bypass errors, and clearing corrupted security credentials.

1. Understand the Cause of Outlook Error 0x80070057

In the Windows operating system, the hex code 0x80070057 maps to E_INVALIDARG (invalid parameter). Within Outlook, this indicates that the Autodiscover engine received configuration parameters from your mail server that are invalid, unparseable, or conflict with your local database structures. Key causes include:

• Autodiscover Redirection Mismatch: Outlook is redirected to a legacy or incorrect server URL during autoconfiguration, yielding corrupted parameters.
• Corrupted Local Profile Registry Keys: Broken registry values within the Microsoft Office path structure return invalid parameters during account handshakes.
• Keychain and Credential Store Conflicts: Old, cached passwords or Security Assertions (SAML tokens) conflict with the new Modern Authentication flow.
• Corrupt Office Installations: Local library dependencies mismatch.

Step 1: Add Registry Overrides

Copy and run these commands in a Command Prompt running as Administrator to inject local Autodiscover exclusions:

:: Exclude HTTPS root domain checks to prevent incorrect redirects
reg add "HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover" /v "ExcludeHttpsRootDomain" /t REG_DWORD /d 1 /f

:: Force Outlook to prioritize local Autodiscover XML configs
reg add "HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover" /v "PreferLocalXML" /t REG_DWORD /d 1 /f

:: Exclude HTTP redirect queries
reg add "HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover" /v "ExcludeHttpRedirect" /t REG_DWORD /d 0 /f

Step 2: Clear Local Autodiscover XML Cache

Outlook caches Autodiscover responses locally. Delete these cached files to force a clean server query:

:: Close Outlook
taskkill /F /IM outlook.exe

:: Clear the autodiscover XML cache directory
del /q /f "%localappdata%\Microsoft\Outlook\16\*.xml"

Step 1: Clean Keycached Sign-ins

1. Close Outlook (killall "Microsoft Outlook").
2. Open Keychain Access (press Cmd + Space, type Keychain Access, and press Enter).
3. Search for the word Exchange and delete all matching login items.
4. Search for Office and delete items starting with:
   • Microsoft Office Identities Cache...
   • Microsoft Office Identities Settings...
5. Relaunch Outlook and enter your credentials again.

Step 2: Switch to Legacy/New Outlook Interface

Changing the rendering interface forces macOS Outlook to build a fresh SQLite configuration store:

• Switch from New to Legacy: Click the Outlook menu in the top bar → uncheck New Outlook.
• Switch from Legacy to New: Toggle the New Outlook switch in the top right corner.

4. Recreate Outlook Profile to Resolve Parameter Errors

If registry edits and cache flushes fail, the configuration database is corrupt and must be rebuilt.

/Applications/Microsoft\ Outlook.app/Contents/SharedSupport/Outlook\ Profile\ Manager.app/Contents/MacOS/Outlook\ Profile\ Manager

5. Summary Diagnostics Checklist