Dear Ismael & Rikard,
Thanks for your great support.
Our site is running well now.

I follow the Dude instruction here:
https://kriesi.at/support/topic/theme-error/
Probably you need to use a database tool to change the value manually. Use a db management tool like phpmyadmin, open your database and search for the “blog_charset” option (without “”) in the wp_options table. Click on “Edit” and make sure that it’s set to “UTF-8” (without “”). >> change from UTF-7 to UTF-8

And it works now.
What a great and best support.
Thanks bro