Execution hangs after 'yarn start'

[framebassman]

When I run 'yarn run start' - execution hangs up. I have the following output:

/usr/local/bin/node /usr/local/Cellar/yarn/1.7.0/libexec/bin/yarn.js run start
yarn run v1.7.0
$ yarn build && yarn setup-selenium && cross-env NODE_CONFIG_DIR=./build/config nightwatch --config=build/nightwatch.conf.js
$ rimraf build && tsc
$ yarn build && node build/scripts/setup-selenium
$ rimraf build && tsc
Starting selenium server in parallel mode...