Harrison was months in research analyzing his fruitless attempts; was it his translation? Perhaps his pronunciation was off. He’d meticulously prepared according to the scroll and yet… nothing.
Your problem is, you expect a 3,000 year-old ritual to work.
It should work; there was too much correlation between the legends, mythologies, and archaeology.
He finally discovered that the incantation was written backward, perhaps to keep it secret.
He tried again the following week in a deserted parking lot, during the full moon when ambient energies were strongest. Now as he spoke the incantation the wind picked up, forming a vortex in the surface of the cracked pavement. Arcs of lightning split the air. Brilliant, inky blackness leaked through from the other side, and fascination became dread as something… incomprehensible emerged.
As darkness invaded his mind, Harrison tried to speak the incantation to close this gate, but found he could not.