How To Fix Unauthorized Google Sheets import

If you have encountered the Unauthorized error, while importing data from your existing Google Sheets application, do the following.

Make sure that you have permission to access the file you are trying to import, by clicking on the file link on the Source Applications page.

If you can't access the file, get the permission or use a google account, that has this permission.
Click on the three dots icon.
On the context-menu, click on the Export Definition option.
A window opens containing the definition of your Google Sheets application. Click on the Copy to clipboard button.
Now open any text editor, like Notepad on Windows or TextEdit on Mac computer, and paste the copied definition in a new file. Save it as a backup, just to be sure not to lose anything.
Go back to flex.bi Source Applications page and click on the Add new source application button on the bottom of the page.
On the next page, click on the Import definition option.
In the Import source application definition window, past the application definition you copied some steps back and then click on the Create button.
On the next page, select the google account that you want to use for accessing the file you want to import.
On the Sign in with Google window, click on the Allow button.
You will be redirected bak to flex.bi and the Source columns mapping page will be opened. Check, if the columns mapping is set and then click on the Start import button. If you have problems with column mapping, contact us at support@flex.bi.
If all is good, the new application imports data and shows status Imported on the source applications list.

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Now you can delete the original application and also its data, to remove duplicated data from your account. To do that, scroll to the original application with the status Error, click on the three dots icon and select the Delete option on the menu.
On the popup that opens, click on the Also imported data button. Don't worry, you are only deleting the duplicated data.