Internal error

[xcld]

When I type in Chinese, submitting and saving this editor will not work. like this

An error occurred on the page you were trying to access.
If you continue to experience problems please contact your Redmine administrator for assistance.

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Environment:
Redmine version 3.4.6.stable
Ruby version 2.3.6-p384 (2017-12-14) [x86_64-linux-gnu]
Rails version 4.2.8
Environment production
Database adapter Mysql2
SCM:
Subversion 1.9.3
Git 2.7.4
Filesystem
Redmine plugins:
bestest_markdown_editor 1.1.0