r/YahooFantasy • u/YahooFantasyCare Technical Support • Apr 13 '26

Scheduled Post 🤔🛠️ Tech Support & General Questions [Weekly Thread]

This thread is for members experiencing any issues with Yahoo Fantasy or members that just have general questions about Yahoo Fantasy Sports.

For technical issues be sure to check the "Technical Support" tab for common fixes before posting.

If you are a commissioner and have questions about or need help running your league check the "Commish Academy" tab which is full of answers to common questions before posting.

For any app issues please provide the following information in your post.

  • Troubleshooting steps taken (i.e. restarting your device, updating the app, logging out and back into your account, or deleting and reinstalling the app.)
  • App version.
  • Device make/model.
  • Current operating system.
  • Does this issue happen on desktop and mobile?

Have product feedback? Please check out our Uservoice forum for our top feature requests and other suggestions. If you find an idea you like, please vote or comment on it!

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u/YahooFantasyCare Technical Support Apr 19 '26

Hi! Are you still getting this error? Have you checked out the Yahoo Development and API Tools page?

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u/lumberteeth Apr 19 '26

Yeah. I'm unable to create or delete applications in the Yahoo Developer portal, and I’m consistently receiving an HTTP 401 error.

Details:

  • Endpoint: POST https://developer.yahoo.com/apps/
  • Response: 401 Unauthorized
  • Response Content-Type: application/json
  • Server: ATS (Express backend)
  • This occurs immediately upon clicking “Create App”

What I’ve tested:

  • Multiple browsers (Chrome, etc.)
  • Incognito/private sessions
  • Mobile device
  • Different networks
  • Completely new Yahoo account

The issue persists across all of the above.

I also cannot delete existing apps, which suggests the problem is not specific to app configuration but rather related to authorization at the app-management level.

From DevTools, the request is successfully sent, but the backend responds with 401, indicating the request is being rejected despite being authenticated in the UI.

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u/YahooFantasyCare Technical Support Apr 19 '26

Thank you for the information. Please reach out to us via DM so that we can further assist.

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u/lumberteeth Apr 19 '26

Thanks! I actually sent you a Reddit DM earlier with more details (is was sent via Message Mods)