SymptomWhen a user is using non-English language for their environment, (e.g. Chinese Traditional language in this case), in email subscription, email subject and attachment subject will display with question marks instead of the report name which should be in Chinese language.

SolutionUncheck "Use US-ASCII for Subject, Attachment Names and Display Names" in MIME options in device.1. Open Devices tab under Administration in Developer;2. Choose the email Device that has been used and edit;3. Click options besides MIME;4. Uncheck "Use US-ASCII for Subject, Attachment Names and Display Names"