I have done a little analysis of and experimentation with Spotify. experimentation: I have setup my Spotify account with a Japanese Katakana username, a Chinese hanzi email address and a Korean hangeul password. Native script forms and not romanised forms. It works!!! How cool is that😀 analysis: Spotify uses google mail. The following is an extract from my terminal session. 苹果电脑 ~: host spotify.com<http://spotify.com> spotify.com<http://spotify.com> has address 194.132.198.149 spotify.com<http://spotify.com> has address 194.132.197.198 spotify.com<http://spotify.com> has address 194.132.198.198 spotify.com<http://spotify.com> mail is handled by 10 ASPMX4.GOOGLEMAIL.com<http://ASPMX4.GOOGLEMAIL.com>. spotify.com<http://spotify.com> mail is handled by 5 ALT1.ASPMX.L.GOOGLE.com<http://ALT1.ASPMX.L.GOOGLE.com>. spotify.com<http://spotify.com> mail is handled by 10 ASPMX5.GOOGLEMAIL.com<http://ASPMX5.GOOGLEMAIL.com>. spotify.com<http://spotify.com> mail is handled by 10 ASPMX2.GOOGLEMAIL.com<http://ASPMX2.GOOGLEMAIL.com>. spotify.com<http://spotify.com> mail is handled by 1 ASPMX.L.GOOGLE.com<http://ASPMX.L.GOOGLE.com>. spotify.com<http://spotify.com> mail is handled by 5 ALT2.ASPMX.L.GOOGLE.com<http://ALT2.ASPMX.L.GOOGLE.com>. spotify.com<http://spotify.com> mail is handled by 10 ASPMX3.GOOGLEMAIL.com<http://ASPMX3.GOOGLEMAIL.com>. I also checked with XgenPlus EAI tester https://eai.xgenplus.com/ using address support@spotify.com<mailto:support@spotify.com> If you run the test yourself you will see the server advertising SMTPUTF8 So, this explains the Chinese email address part working, as google supports EAI. André Schappo