Hey Hkz0r, I can get shut out a bit kinda like you as well. I know the dimly lit room. I was told "Come back when you understand better", when I was there last. Another time I smoked with a less pure intention and was shut out into a golden tunnel, with my eyes both open and closed I could see exactly the same thing. Just a tunnel with golden light. I was stuck between worlds.
DmnStr8's advice has worked for me. Taking breaks of at least a week between flights and knowing/understanding my intent clearly has helped a lot. If I smoke and my reasoning isn't right I find it doesn't open in the same way. My body and mind adapted very quickly to DMT and created rules/requirements for me to follow. If I don't adhere I don't get to see the magic.
Only the pure of heart get to stand before the spirits... maybe.
The nearest we ever come to knowing truth is when we are witness to paradox.