B.G 9.24
I am indeed the enjoyer and the sole Lord of all sacrifices; but they do not truly know Me in essence - therefore, they fall away.
Gīta Bhāshya 9.24
Any worship that does not recognize lord Krishna as the enjoyer and the sole Lord of all sacrifices is improper.
The reason for their worship being improper is stated in the verse beginning with "ahaṁ hi".
Gīta Tātparya 9.24
'na tu mām abhijānanti tattvena' - they do not know me truely based on underlying principles. Hence they fall down. Therefore, one must understand the supremacy of Lord Vishnu as the highest, and deities Brahma and others as his subordinates.
Those who superficially worship and pray to Me because they've been told to, even though they know, do not understand Me in principle.
"The one who does not know the Lord Keshava, soon his merits become futile by the boons given by other deities, and he goes to the deepest darkness".
- stated thus as well.
It is said that those who have futile hopes and futile actions, who have mere superficial knowledge or wrong knowledge, "fall away from their goal". Therefore, one must understand the supremacy of Lord Vishnu as highest, and deities Brahma and others as his subordinates. If they don't (understand so) the results are as stated.