Many international companies send localized holiday wishes to their mailing lists based on the recipient's IP address or registration data.
Croatian (also used in Bosnian and occasionally Serbian, though "Srećan Božić" is more common in Serbia). Sretan BoЕѕiД‡
The string is a classic case of Mojibake (text decoding errors). The Croatian letter ž was misinterpreted as Еѕ . The Croatian letter ć was misinterpreted as Д‡ . Sretan BoЕѕiД‡