This is the only thing that comes to my mind: means that at runtime the Jakarta Dependency Injection API (JSR-330) isn’t on your classpath. Spring Boot 3 / Spring Framework 6 fully migrates from javax.inject to jakarta.inject, so you must include the Jakarta DI API JAR (which contains the jakarta.inject.Provider interface). Spring Boot 3’s own BOM will bring it in automatically only if you align your Spring Cloud version correctly and/or rely on the Boot 3.3+ dependency management.