The purpose of this study is to investigate the challenges of emergency online teaching and learning adopted in a Nigerian private university due to the suspension of face-to- face learning, as a result of the COVID-19 pandemic. Activity theory was used to examine the elements that make up the activity, that is, the virtual learning environment, as well as their associated relationships in order to reveal existing and potential tensions within the activity. Data used for the analysis of this case study was obtained by observation of the online class sessions, student responses to an online survey, emails (requesting support) received by the instructional technology support team, and interviews with participants of the activity system. The findings show that majority of the challenges and contradictions observed were a result of a hurried decision to migrate to online learning in order to complete the academic semester. This brought about several issues with regards to the tools, rules, and roles within the activity system. The most significant contradiction observed was as a result of the influence of an external activity on the studied activity system. The study provides insights to policymakers in the education sector on the current barriers to online learning, especially in the Nigerian context.