Error: "Error 105 - Authentication failed"

Hi Paddy Ogee,

Thank you for reaching out to the Microsoft Advertising Learn Q&A Platform!

The error you're encountering "Error 105 - Authentication failed", typically indicates that the developer token you're using is either not approved, expired, or not correctly associated with the account you're using to authenticate.

Here are a few things to check:

1. Developer Token Status: Unfortunately, the system doesn’t explicitly show “approved” or “denied” statuses in all cases. If your token is not marked as “pending” or “denied,” it might be approved, but this isn’t guaranteed. The safest way to confirm the status is to check in the Developer Portal or contact support directly.

Account Association: Ensure that the developer token is correctly associated with the account you're using for OAuth. Even if OAuth is working and you're receiving access tokens, the token must be linked to the same account.

Legacy Account Prefix ("X16..."): Having a legacy account doesn’t automatically guarantee token approval. If your account is older, there may be additional verification steps or migration requirements.

Token Expiry: Developer tokens can expire or be revoked. If you haven’t used it in a while, it’s worth checking if it needs to be renewed.

To resolve this, I recommend:

• Logging into the Microsoft Advertising Developer Portal to verify the token status.
• Reviewing the authentication documentation for Microsoft Advertising API: Authentication Guide.  

Bing Ads API Concepts - Microsoft Advertising API | Microsoft Learn

I hope the information provided here will at least partly answer your question.  If you have any additional questions please do not hesitate to reach out to our support. 

Kind regards, 

Arsen D. | Microsoft Advertising Support Specialist | 800-518-5689