How should I fix "Content is not allowed in prolog" React-Native error?

I am facing an embarrassing error on my react-native project.
I tried to remove the content in string.xml file but I still get the following error:

Execution failed for task ':app:mergeDebugResources'.  
E:\New folder\jeeps\android\app\src\main\res\values\strings.xml:1:1: 
    Error: Content is not allowed in prolog.