It is certainly a font problem in your OS.
In case of Chinese, it was reported that "yum groupinstall chinese-support" has fixed the problem. So you may do the same with your own language.
Otherwise you can try to add DejaVuSansMono.ttf or DejaVuSans-Bold.ttf in your server and to setup a fonts.conf alias in your server:
<test qual="any" name="family">
<edit name="family" mode="assign">