Without your explicit permission, lembot cannot edit your Google Sheets and you will get a Google API error [403] The caller does not have permission
.
Giving permission is super easy.
As easy as sharing the spreadsheet to your best friend, with editor
rights.
Here your best friend is lembot which email is:
lembot@lembot.iam.gserviceaccount.com
Even easier but I do not recommend because it is less secured.
Click Get link, choose Anyone with the link and select Editor rights.
Cheers,
François