Chinese language doesn't work for Question for Confluence

Step to reproduce :
1. install Question for Confluence on Server
2. Change the language to Chinese

Expected behaviour
Question for Confluence would be translated in Chinese

Actual behaviour
Question for Confluence remains in English

Additional information

• Tested with Korean, Japanese, French, Dutch, and those language packs are working with Question for Confluence (Question for Confluence is translated in those languages)
• Tested with the lastest version QaA 2.6.6