ERROR: Unable to parse file: file:///var/lib/jenkins/workspace/petstore/Dockerfile

I am working on this project using jenkins. While trying to run the pipeline, getting an error.

ERROR: Unable to parse file: file:///var/lib/jenkins/workspace/petstore/Dockerfile. 
ERROR: Cannot parse 'Dockerfile': begin 2, end 1, length 1

Do anyone have an idea on this?