This study evaluated the CTU Registrar Portal's usability using the ISO 9241-11 model, employing think-aloud protocols and SUS assessments with the university’s alumni and current students. Remote testing revealed significant differences in task efficiency between groups, highlighting the impact of learnability. Moreover, common errors, technical glitches, and usability challenges were identified. Exit interviews also revealed interface disorientation, accessibility issues, and counterproductive portal features. Based on these findings, recommendations are proposed for portal improvements, including login, homepage, and request page refinements, to enhance user experience.