Error message : Failed to install the following Android SDK packages as some licenses have not been accepted.
This is kine of normal issue for early stage development of mobile app using React-Native. Follow the step below to resolve this issue by accepted all the required licenses.
For windows users :
On your command prompt (CMD), point the directrory to your SDK folder
cd $ANDROID_HOME/tools/bin
next insert this command
sdkmanager --licenses
you need to enter letter ‘Y’ to accept all the required licenses.
After all required licenses has been accepted, rebuild your app.
Other Reference : stackoverflow.com