Agile methods have become a standard practice within software industry, with organizations increasingly adopting large-scale agile (LSA) frameworks. However, as these frameworks are implemented across multiple teams and organizational functions, new challenges emerge, particularly in maintaining alignment, coherence, and collaboration across teams. One crucial element in addressing these challenges is fostering of a culture of continuous learning and psychological safety, with the objective of optimizing team performance and ensuring project success. Despite the importance of this topic, there is a significant gap in existing literature regarding antecedents of psychological safety and its impact on team learning and performance in LSA environments. This study aims to investigate impact of high-quality relationships and psychological safety on learning from failures and, consequently, on team performance in LSA context. An online survey of 167 software professionals in Sweden was conducted to test a conceptual model that is developed based on existing literature. The hypotheses were analyzed using partial least squares structural equation modeling. The results demonstrate strong positive correlation between the presence of high-quality relationships, psychological safety, and capacity to learn from failures and team performance. Specifically, the formation of high-quality relationships has been demonstrated to significantly enhance psychological safety, which in turn facilitates learning from failures and leads to improved team performance. These findings offer valuable insights for both practitioners and researchers, highlighting the importance of cultivating relational dynamics and a psychologically safe environment in LSA projects. Furthermore, the study offers guidance for future research, regarding the scalability and generalizability of these findings.