How can I fix these launch errors?

In every time that I’m trying to launch my project, These errors pop up:

LogPlayLevel: BUILD FAILED in 9s
LogPlayLevel: Error: ERROR: /bin/sh failed with args -c '"/Users/alon/Documents/Unreal Projects/FirstTest/Intermediate/Android/armv7/gradle/gradlew" :app:assembleDebug'
LogPlayLevel:        (see /Users/alon/Library/Logs/Unreal Engine/LocalBuildLogs/Log.txt for full exception trace)
LogPlayLevel: AutomationTool exiting with ExitCode=1 (Error_Unknown)
LogPlayLevel: Completed Launch On Stage: Build Task, Time: 18.486435
LogPlayLevel: Error: RunUAT ERROR: AutomationTool was unable to run successfully.
PackagingResults: Error: Launch failed! Unknown Error

How can I fix them?
Thank you in advance.