It’s hard to say without knowing how you’ve set up your credentials, but a good place to start would be to take a look at the docs here Google: Service Account and
check if you haven’t missed anything. e.g. have you enabled Google Drive API as well as Google Sheet API? (something I overlooked when setting this up)
Thanks @aya for your reply. I have followed those steps exactly. There is another sheets node (Get emails) just before update last contacted time google sheets node., it works well there. For this node. it is still throwing me the error.