This study investigated the issues encountered when interacting with Namibia's online self-service taxation system, the Integrated Tax Administration System (ITAS). ITAS aims to efficiently collect taxes with the least amount of costs to the administration and taxpayers by providing online self-tax services. While cost-effectiveness and efficiency are priorities for ITAS, system complexity may have a negative impact on the user experience. Namibia relies significantly on tax revenue; thus, ensuring the satisfaction of authorities and taxpayers requires evaluating the usability of the ITAS. Through qualitative techniques, open-ended questionnaires, and follow-up interviews, we investigated the challenges faced by corporate and individual ITAS users (n = 14). The findings indicate that there are difficulties in utilizing the tax return service and that there are speed, navigation, and usability issues with the system. The participants’ identified issues such as confusing instructions, broken systems, and time-consuming processes. Despite these challenges, there are certain benefits to the system, such as convenience and accessibility. The study highlights how important it is to address user concerns to increase overall tax administration efficacy and optimize ITAS performance. Among the suggestions include strengthening user training, enhancing system stability, optimizing system navigation, and streamlining communication channels. By implementing these strategies, tax administration organizations can enhance user experience, promote compliance, and speed up tax-related processes.