Explains why you may see question marks print on labels when non-roman characters have imported for the order, and steps to take to resolve.
The Issue
Character sets like Japanese, Chinese, and Cyrillic are often not supported by the carrier's label API, resulting in ??? symbols or blank space on the label where the characters should be.
Many carriers in English-speaking countries, including FedEx and UPS, require that the full Ship To address - including the full country name - appear in Roman characters. You can sometimes use non-English text for the address on the label if the names of the city, province, and country are in English.

What to Do
Translate the address into English by either requesting it from your customer or using a program like Google Translate. Then update the address in ShipStation to the English translation.
Notice
The ShipStation Open API does not support non-Roman characters.