AppSheet Automation PDF Generated Successfully but File Column Returns "URL has an invalid signature"

AppSheet AppSheet Q&A
1

Hello AppSheet Team,

I am experiencing an issue with a PDF generation workflow in AppSheet.

Environment:

  • AppSheet app connected to OneDrive Personal
  • PDF generated using Automation (Create a new file task)
  • File stored in /GeneratedData folder
  • File column used to reference the generated PDF

Issue:
The PDF file is generated successfully and physically exists in OneDrive. However, when clicking the File column inside AppSheet, the file cannot be opened and AppSheet returns:

“Error retrieving file ‘/GeneratedData/KPLH.pdf’: URL has an invalid signature”

What I have verified:

  1. The Automation task completes successfully.
  2. The PDF file is created in OneDrive.
  3. The file path stored in the File column exactly matches the generated file:
    /GeneratedData/KPLH.pdf
  4. The file can be opened directly from OneDrive.
  5. I tested both:
    • /Files/
    • /GeneratedData/
  6. I regenerated the table structure and synchronized the app.
  7. The issue occurs even when the file exists and the path is correct.

Comparison:
I have another AppSheet application using the same OneDrive account and the same PDF generation pattern:

Automation:

  • Folder: /GeneratedData
  • Dynamic File Name Prefix

File Column Formula:
CONCATENATE(“/GeneratedData/”, [FileName], “.pdf”)

In that application, the generated PDF opens correctly through the File column.

In this application, using the same approach, the PDF is generated but AppSheet always returns:
“URL has an invalid signature”

Expected Behavior:
The File column should open the generated PDF, just as it does in the other application.

Could you please help identify why AppSheet is unable to generate a valid file URL signature for files that clearly exist in the storage location?

Thank you.

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2

Please try toggling with the following option.

In my experience, switching off “Secure PDF access” once and then switching it on again works.

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3

Hi @Imam_Fauzzi

Try checking the following links Struggling with AppSheet? Drop your problem here — I'll help you figure it out - #12 by Syamsudin and .

is that what you are looking for?

4

hy syam, thankyou for answering, i been trying and it still doesnt work , i still dont understand how to call file that we created on appshet, the file is created and i can see it on onedrive

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5

it still doesnt work :frowning:

6

Have you changed the Google drive folder from restricted to anyone with the link? And does a timestamp appear in the PDF file name? If so, disable the time stamp?

7

Hello,

Thank you for sharing the detailed information regarding the issue.

To help narrow down the possible cause, could you please confirm whether the GeneratedData folder shown in your screenshot is located within the same parent folder that contains the app’s data source files (tables) in OneDrive?

In other words, we would like to verify if both:

  • The app data source files, and

  • The GeneratedData folder where the PDFs are being created

are stored under the same AppSheet app folder structure in OneDrive.

Since AppSheet is successfully generating the PDF but later reports an invalid URL signature when accessing it through the File column, confirming the folder structure will give us a useful starting point for further investigation.

If possible, please also share a screenshot of the folder hierarchy in OneDrive showing:

  • The app data source files

  • The GeneratedData folder

  • The generated PDF file

This information may help identify any differences between the application that works correctly and the one experiencing the issue.

Thank you, and we look forward to your response.