Cardale garage door operation

I have a Cardale garage door that I want to open manually. My remote fob has decided not to work and I cannot transfer the current code to a new fob. There is a handle/lock near the bottom of the door which only turns 45 degrees and not the expected 90 degrees and therefore the door will not open (there is not any other access to the garage). Is the door locked against the mechanism electrically and has to be released somehow?

Thanks.

There should be a red release rope on the rail by your trolley. Bif not just disconnect your "j" arm from your door.