Make sure your spreadsheet file is uploaded to somewhere Geckoboard can access, with permissions set to be visible to 'Anybody with the link'.
See steps for these popular cloud services:
Due to limitations with OneDrive Personal, the free version of Microsoft's cloud storage, and its lack of support for downloadable files through a share link, OneDrive Personal is not currently supported for hosting .xlsx files.
Google Drive
Click the Share button in the top right-hand corner.
Set your spreadsheet file to be visible to Anyone with the link.
Click Copy link to copy your sharing link.
Switch to Geckoboard, then paste your share link into the Link to file field.
OneDrive for Business or Sharepoint
Select your spreadsheet file, click Share, then select Copy link.
Then click Settings.
Scroll down to the More settings drop-down and open it.
Set the permission to Can edit, then click Apply.
Select Copy link again if needed.
Switch to Geckoboard, then paste your share link into the Link to file field.
Dropbox
Hover over the Spreadsheet file you’d like to share, then click the share icon.
From the dropdown, select can edit.
If a link hasn't been created, click Create.
If a link has been created, then click Copy link.
Switch to Geckoboard, then paste your share link into the Link to file field.
