Unable to read pdf using tabula-py

Question

I am trying to parse a pdf using tabula-py but I keep getting this error stack -

CalledProcessError(1, ['java', '-Dfile.encoding=UTF8', '-jar', '/home/ubuntu/.local/share/virtualenvs/my-project-9AYKFKDB/lib/python3.6/site-packages/tabula/tabula-1.0.4-jar-with-dependencies.jar', '--pages', 'all', '--lattic

Here is code -

 import tabula
    @app.route('/test', methods=['GET'])
    def test():
        df = tabula.read_pdf("file.pdf")

When I try to parse the pdf via the command line, it works

java -jar /home/ubuntu/.local/share/virtualenvs/my-project-9AYKFKDB/lib/python3.6/site-packages/tabula/tabula-1.0.4-jar-with-dependencies.jar --pages 1 /home/ubuntu/my-project/file.pdf 

My Pipfile looks like this

[[source]]
name = "pypi"
url = "https://pypi.org/simple"
verify_ssl = true

[dev-packages]

[packages]
flask = "*"
tabula-py = "*"

[requires]
python_version = "3.6"

Please what might be the problem?