What green lights are flashing?
If you number them from left to right with 1 on the left which number lights are flashing as i assume the end light is lit solid?
Thanks for that.
The lights flashing is an error code and the error code its reporting is E6 which is a time out draining fault.
What you need to do is first check the waste pipe and were it drains to. Make sure its all clear in there.
If thats fine then you need to access the drain pump underneath the dishwasher and remove this and check for debris in there. Also make sure the pump impeller can ping round in stages. If its stiff to turn then the pump is faulty and will need to be replaced on this.
Retry it and then see how it goes from there. Fingers crossed its just a blockage thats casuing this fault as thats what the flashing lights mean its a pump fault error code on this.
No worries, If you need more help then just get back to me.