I just got Canon XL-1 and when I insert a MiniDV trape it gives the "no tape" indication and it will not record.
I read the Manual thoroughly and the tape is not locked.
Any idea why the camera is doing this?

The usual issue is not pushing in the tape caddy before the door is closed.

Push the tape caddy IN to the body (where it says "PUSH close this first"). This allows the tape to load. Then close the door.