The present qualitative study aimed to explore and understand reasons why insured persons under Social Security Act Article 40 missed paying contribution. Two data collection methods were used. First, telephone interviews, data were collected from nine village labour volunteers and community-based social security network members for Article 40 and one insured person who had experiences with Article 33, 39, and 40. The informants were from Lamphun, Burriram, Khon Kaen, Bangkok, and Phuket. Second, online public comments related to Social Security Act Article 40 published during 2011-2021 were reviewed. The findings showed that reasons the insured persons under Article 40 missed contribution payment included: too complex procedures of benefit claim, less elderly lump sum than expected, unequal benefits compared to other insurance schemes, not knowing the consequences of missed contribution payment, not knowing what and how to do when having missed contribution payments, being unaware of contribution payment deadline, inconvenience with available contribution payment channels, and poverty. These findings suggest eliminating barriers and improving ease of claiming benefits, raising awareness of health risks and consequences of missing contribution payments on benefit claims, and developing out-reach communication for contribution payment alert system, and easy to access contribution payment methods in remote communities.