Solve the SpringBoot startup error No converter found capable of converting from type [java.lang.String] to type [org.s

When I started Spingboot this afternoon, I found that the console reported the following error:
No converter found capable of converting from type [java.lang.String] to type [org.springframework.boot.autoconfigure.web.servlet.WebMvcProperties$Contentnegotiation]

After investigation, it was found that there was a problem with the configuration in the yaml file. Just comment the following code.