Travis CI build fails on react-native android

I am trying to build my react-native project with travis ci using this command:

script: 
    - npm install -g npx && cd android && sudo chmod +x gradlew && sudo ./gradlew assembleRelease#3

However, my build fails with the following error: Cannot run program "npx": error=2, No such file or directory

My full config if as follows:

language: android
before_install: #1.1
- nvm install 10
- node --version
install: #1.2
- npm install
android: #1.3
  components:
  - build-tools-23.0.1
  - android-23
  - extra-android-m2repository
  - extra-google-google_play_services
  - extra-google-m2repository
  - addon-google_apis-google-16
script: 
    - npm install -g npx && cd android && sudo chmod +x gradlew && sudo ./gradlew assembleRelease#3
deploy: # mostly generated by `> travis deploy releases`
  skip_cleanup: true

It seems as though the build file is unable to find npx even though I have installed globally with npm. In the native_modules.gradle files where the errors, the error line is as follows:

def npx = Os.isFamily(Os.FAMILY_WINDOWS) ? "npx.cmd" : "npx"

Here is a call stack where the error occurs:

Welcome to Gradle 5.5!
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Here are the highlights of this release:
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 - Kickstart Gradle plugin development with gradle init
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 - Distribute organization-wide Gradle properties in custom Gradle distributions
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 - Transform dependency artifacts on resolution
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For more details see https://docs.gradle.org/5.5/release-notes.html
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Starting a Gradle Daemon (subsequent builds will be faster)
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> Starting Daemon<-------------> 0% INITIALIZING [21ms]<-------------> 0% INITIALIZING [121ms]> Evaluating settings<-------------> 0% INITIALIZING [221ms]<-------------> 0% INITIALIZING [321ms]<-------------> 0% INITIALIZING [421ms]<-------------> 0% INITIALIZING [521ms]<-------------> 0% INITIALIZING [621ms]<-------------> 0% INITIALIZING [721ms]<-------------> 0% INITIALIZING [822ms]> Evaluating settings > Compiling /home/travis/build/daniel-sudz/bbox-mobile/an<-------------> 0% INITIALIZING [921ms]<-------------> 0% INITIALIZING [1s]> Evaluating settings> Evaluating settings > Compiling /home/travis/build/daniel-sudz/bbox-mobile/no> Evaluating settingsmand from 'null' directory failed.
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FAILURE: Build failed with an exception.
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* Where:
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Script '/home/travis/build/daniel-sudz/bbox-mobile/node_modules/@react-native-community/cli-platform-android/native_modules.gradle' line: 154
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* What went wrong:
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A problem occurred evaluating script.
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> Cannot run program "npx": error=2, No such file or directory

Note: the build occurs on ubuntu

Any ideas on what the solution may be?