How did Husserl’s ideas raise the problem of solipsism?

Edmund Husserl’s phenomenological method led to the problem of solipsism because of his reliance on the transcendental ego as the foundation for all meaning.1

To achieve a presuppositionless science, Husserl employed the epochē—a technique of "bracketing" or suspending belief in the existence of the external world to focus exclusively on the contents of consciousness. By performing this phenomenological reduction, Husserl aimed to isolate the transcendental ego, which he viewed as the source that "constitutes" objects.234

Because this transcendental ego appeared to be the only genuinely existent consciousness remaining after the world was bracketed, Husserl faced the challenge of explaining how knowledge of other minds or an external world could be justified. This focus on the ego as the primary ground of experience made his work susceptible to the charge of radical subjectivism, as it seemed to isolate the individual within their own consciousness, thereby raising the problem of solipsism. Husserl attempted to address this gap in his later work, Cartesian Meditations.24