Error message

Login failed: Error from MasterTrust: [invalid_client - Client authentication failed]

Last updated 9 July 2026

MasterTrust: invalid_request / invalid_client login error

In short

These MasterTrust login errors mean your MasterTrust API app is not set up correctly. 'invalid_client' means the client id or secret does not match; 'invalid_request' usually means the redirect URL on your MasterTrust app does not match the one required. Check your API app's redirect URL and client id/secret against the MasterTrust setup guide, correct them on your account, then Validate & Save.

When this happens

  1. 1 The redirect URL set on your MasterTrust API app does not match the one required (invalid_request).
  2. 2 The client id or client secret saved for the account is wrong (invalid_client).

Errors

This fix applies to these MasterTrust login errors:

  • invalid_request - The request is missing a required parameter, or the redirect_uri does not match.
  • invalid_client - Client authentication failed (unknown client, or wrong client credentials).

What this error means

MasterTrust rejected the connection because your API app is not set up correctly:

  • invalid_request usually means the redirect URL registered on your MasterTrust API app does not match the one AutoTrader needs.
  • invalid_client means the client id or client secret saved for your account is wrong.

How to fix it

  1. Open your MasterTrust API / developer app settings.
  2. Make sure the redirect URL matches the one shown in the MasterTrust setup guide.
  3. Check that the client id and client secret are correct.
  4. In AutoTrader Web, go to Accounts → Trading Accounts, correct the values on your MasterTrust account, and click Validate & Save.

See your broker setup guide for the exact values. If it still fails after this, please contact us.

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