Build Error. npm ERR! 404 Not Found: pinkie-promise

[MMrj9]

Type of problem

• Failure to build

  Summary

  My app builds and runs locally without any problems. But it fails to build to heroku.

Contents of .meteor/release

METEOR@1.6.0.1

Buildpack version

https://github.com/AdmitHub/meteor-buildpack-horse.git

Logs

remote: npm ERR! code E404
remote: npm ERR! 404 Not Found: pinkie-promise@https://registry.npmjs.org/pinkie-promise/-/pinkie-promise-2.0.1.tgz
remote: 
remote: npm ERR! A complete log of this run can be found in:
remote: npm ERR!     /app/.npm/_logs/2018-01-06T20_58_42_718Z-debug.log
remote:  !     Push rejected, failed to compile Node.js app.
remote: 
remote:  !     Push failed

Deployment target

Heroku

Any help would be appreciated!