Cannot resolve symbol 'SpringApplication'

This error usually occurs when the Spring Boot application dependencies are not properly configured in the project. Here are some potential solutions:

1. Make sure that the Spring Boot dependencies are added to the project's build file (e.g. pom.xml for Maven or build.gradle for Gradle). You can add the following dependency for Spring Boot Starter:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
</dependency>

2. Check if the Spring Boot version specified in the project's build file matches the version used in the code. If not, update the version accordingly.

3. If you are using an IDE like IntelliJ or Eclipse, try refreshing the project or restarting the IDE.

4. If none of the above solutions work, try deleting the local repository (usually located in ~/.m2/repository for Maven) and rebuilding the project.

If the error persists, please provide more details about your project setup and code so that we can help you better.