[Koha] problem with fonts

Dear friends, I am writing you again due to our problems with fonts in koha 3.8. When we search for a book in the OPAC the search engine retrieves the record.  http://93.187.162.200/cgi-bin/koha/opac-detail.pl?biblionumber=4 However, when we try to browse the catalog using the author's name as a search keyword (i.e. by clicking on the author name displayed in the record), nothing is found. In the search box, instead of the author's name, some strange symbols appear.  http://93.187.162.200/cgi-bin/koha/opac-search.pl?q=au:%C3%94%C2%B9%C3%95%C2..., In the previous version of koha we have not encountered such a problem. Any advises?  Regards, Haik.