Cannot run locally

Hi, I tried as the README that deploys on Heroku, which successes in response to the URL, however when I tried to run locally with command

`node web.js`

The same URL will always show errors about the phrase of the JSON file.

`SyntaxError: Unexpected end of JSON input
at JSON.parse ()
at _processStopped (/Users/harbour/Desktop/graph_planner/cloud-solver/web.js:190:23)
at ChildProcess.exithandler (child_process.js:397:5)
at ChildProcess.emit (events.js:400:28)
at maybeClose (internal/child_process.js:1055:16)
at Socket. (internal/child_process.js:441:11)
at Socket.emit (events.js:400:28)
at Pipe. (net.js:675:12)
`

The URL is
`http://127.0.0.1:5001/solve?domain=http://www.haz.ca/planning-domains/classical/blocks/domain.pddl&problem=http://www.haz.ca/planning-domains/classical/blocks/probBLOCKS-4-1.pddl`
and
`https://safe-dusk-54737.herokuapp.com/solve?domain=http://www.haz.ca/planning-domains/classical/blocks/domain.pddl&problem=http://www.haz.ca/planning-domains/classical/blocks/probBLOCKS-4-1.pddl`

Any help?