After camrecording dvd shows blank

hi, I have a sony dcr - dvd608e pal handycam.
it records to a minidvd.
once I did a recording. but afterwards the dvd shows blank. and the dvd could not be finalized.
computer too shows the dvd as a blank one.
is there a anyway to recover the video ? it is very valuable to me.

I’d go back through the manual, carefully: