Sometimes, it happens that while receiving new tickets in the Helpdesk plugin, some of them cause Redmine error with the following message:
dispatch error Mysql2::Error: Incorrect string value: '\xE2\x80\x8B\xE2\x80\x8B...'
Usually, such errors mean that:
1. Your DB encoding is not completely changed to UTF-8.
2. Try to use utf8mb4. It makes it possible to store more bytes symbols.