Forum Discussion

happy30's avatar
happy30
Copper Contributor
Apr 16, 2026

[DataFormat.Error] We received a malformed web response and credentials issue

Hi team :)
Happy Friday !!

There is an excel spreadsheet being connected with data sources and shared with users. Upon, hitting data refreshes it asks every user to edit credentials every time they hit data refresh or shows dataformat.error with malformed web response. There is no data format error though.

 

Can anyone please assist here or know how to solve this issue ??

 

Thanks

Happy

admin
excel
Excel for web

1 Reply

  • NikolinoDE's avatar
    NikolinoDE
    Platinum Contributor
    Apr 18, 2026

    Cached credentials cause authentication conflicts. When users refresh, Excel reuses expired tokens, leading servers to return HTML login pages instead of data—triggering the error.

    Fixes:

    1. Clear Global Permissions: Data > Data Source Settings > Global permissions > remove data source entries > refresh.
    2. Clear Cache: Use Office Upload Center (Windows) + browser cookies for office.com, login.microsoftonline.com, and data source domain.
    3. API Tokens: If possible, use ?api_key=XXX in the URL to bypass credential prompts.

    Critical: All users must sign in with the same method (e.g., Organizational account) post-clear to avoid token conflicts.

     

    My answers are voluntary and without guarantee!

    Hope this will help you.