COVID-19 are causing many psychological impacts and change many aspects of human life. Mental health services also experiencing changes because of COVID-19 outbreak. In Indonesia, COVID-19 outbreak prompted the rapid development of online mental health services. These online mental health services which will help people to connect with professional mental healthcare providers using technology were created in response to this pandemic. Therefore, converting mental health services into online services in a state of urgency is challenging. This qualitative case study aims to provide a map of the service challenges that professional healthcare providers face while providing online services at present time by interviewing eight Indonesian psychologists as one of the mental health professionals who provided the online mental health services. Semi-structured interviews were done using interview guidelines with open-ended questions, and any other complementary data was collected using questionnaire. The data gathered from interviews was first performed through triangulation and then analyzed using thematic network analysis, which resulted in the following challenges: (1) building engagement; (2) risk of getting distracted during the sessions; (3) maintaining professional boundaries during the sessions; (4) keeping the personal information and confidentiality of the sessions; (5) perceived efficacy; and (6) attitudes towards online sessions. According to the results, the relevant organization can use this finding to contribute and develop the online mental health services both in this COVID-19 situation and in the future.