Spring Boot : Social Auth Errors and Fixes - 2020

I got the following error when I tried to run Spring Boot app:

$ ./gradlew bootRun
"A child container failed during start"

This error is tough to fix because it could happen from anything!

This usually happens when the port is being used.

For instance, when we run an app via mvn spring-boot:run which needs port 8080. So, either the port is already opened for Tomcat or other apps.

We need to kill the app:

$ sudo service tomcat stop

Then, issue the command again.