Read the passage and answer the following question:
"The advent of digital technology has significantly transformed the landscape of education. Online learning platforms, virtual classrooms, and interactive resources have become integral to contemporary teaching methods. While these innovations offer numerous benefits, such as increased accessibility and flexibility, they also present challenges. For instance, the digital divide remains a significant barrier, with students from underprivileged backgrounds often lacking reliable internet access and technological devices. Educators must navigate these complexities to ensure that the advantages of digital learning are equitably distributed."
What is the primary challenge mentioned in the passage regarding digital technology in education?