Ticket notification question marks instead of japanese signs

[ThomasPL10]

Hello all

In my OTRS 5 environment I've got such an issue. I need to implement ticket notification, in the notification body there are japanese signs.
I can paste the japanese letters into the "Text" window but when I click on "Submit" the japanese/asian signs (and only them) change into question marks "?". Regullar letters works fine.

In this ticket notification there is also ticket's subject and if there are some japanese signs in ticket subject they are also shown correctlly.

Thank you in advance for your hints.

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