Upon a closer look

I looked up the word futile in reference to my reading of Ecclesiastes and I also looked more at the phrase that was used 29 times, under the sun.

Futile-
incapable of producing any result; in effective, useless; not successful

lack of effectiveness or success or quality of having no useful result

lack of meaning or purpose.

Our efforts are futile without God!

"under the sun"
I took it as meaning "on earth" but maybe looking deeper it means "a live without God"

Ecc 8:9 All this I have seen and applied my mind to every deed that has been done under the sun wherein a man has exercised authority over another man to his hurt.

I found this by R.C. Sproul that I think sums things up quite nicely and I can understand.

The utter meaninglessness of life from an earthbound perspective that does not take into account the creator God is one of the main points of the book of Ecclesiastes. Again and again, the Preacher contrasts life “under the sun” with “life under heaven,” the former referring to the perspective that looks at everything and concludes that the only thing that exists is what is visible to the human eye. The conclusions that logically flow from such a perspective are presented repeatedly in Ecclesiastes, only to be refuted from the vantage point that sees things “under heaven” — in reference to the covenant Lord of Israel.

Under the sun, everything is vanity (Eccl. 1:2–3). The term vanity comes from the Hebrew word hebel, which means something like “vapor” or “breath.” What is being conveyed is fleetingness. Like vapor, everything is fleeting apart from reference to the Creator, and therefore everything is ultimately futile. Hard work produces gain for the worker for only a short while until his death (vv. 3–4). People run after new sights and sounds to entertain them, but nothing can satisfy (v. 8). Men and women strive to fill the emptiness they feel, but all their efforts are to no avail.

Only the existence of the transcendent God can provide us with any meaning. Life lived with reference to Him — under heaven — is never an exercise in futility.

As Christians, we are to live life “under heaven” — aware of the Lord who sees us and who will render judgment on what we have done. This means we should be serious about learning His will and fulfilling it in all that we do. On the one hand, the Lord’s grace means we should not fear that He is out to get us when we fail. On the other hand, we must not take this grace for granted but strive to live lives of service to our great King.