The machine asks for whatever you tell it to print on, the driver will default to A4 or Letter, so if you did not go into the print driver and set a custom size, then the application did because of the file itself, and since you don't list what the application is, there is no further help I/we can give.
I didn't put in a specific, size, I just sent the report. I wasn't sure there was a way so request a specific size but there must be something somewhere that is doing that.
Either cancel the job requesting the size and send it again without calling for a custom size, or load that paper to print the job