In response to the Covid-19 pandemic, several precautionary measures were imposed in the vast majority of the countries to mitigate the rapid spread of the contagion. Many activities, and institutions, including schools were closed. In Oman, the Ministry of Education (MOE) has turned from the traditional face-to-face to blended learning as an emergency alternative to maintain learning continuity. The MOE provided the first cycle schools with the Mandhara e-learning platform. This platform was designed and established by MOE and used in a relatively short time; therefore, its quality and usability may be prone to technical and instructional-related gaps and errors. This descriptive study aimed to evaluate the quality of the processes and practices in Mandhara e-learning platform based on first-cycle schools' teachers' perceptions and to explore the challenges that these teachers faced while using Mandhara platform in online teaching during Covid-19. To answer the research questions, a mixed method approach was used, with an online questionnaire developed and used to evaluate the platform's quality based on the second part of the Canadian Recommended E-learning Guidelines. The questionnaire sample included 361 first-cycle school teachers from Muscat and Al-Batinah North Governorates. In addition, semi-structured interviews were conducted with six teachers to investigate the challenges they faced while using the Mandhara during Covid-19. According to the findings, the processes and practices in Mandhara have a medium level of quality as perceived by the first cycle school teachers. The findings also revealed that there are no statistically significant differences in teachers' perceptions of Mandhara quality caused by the differences in teachers' ICT competency levels. Finally, the study found that the most serious challenge that teachers faced was the poor and expensive internet network services. The findings also revealed other challenges including lack of students' engagement, lack of technical support, and lack of ICT skills. Based on the findings, the study recommended the MOE to work with the internet network providers (Omantel, Ooredoo and Vodaphone) to develop the internet network services within the schools. The recommendations also included providing first cycle schoolteachers with professional development programs that enhance and develop their ICT skills, improving the schools' technical support services, and conducting a comprehensive quality evaluation that involves the participation of all stakeholders.