When I try to cite more than two authors, I got this:
! Package inputenc Error: Unicode char (U+200B)
(inputenc) not set up for use with LaTeX.
\documentclass[a4paper,oneside,BCOR=10mm,12pt,titlepage]{scrreprt}
\usepackage[polutonikogreek,ngerman,english]{babel}
\usepackage[maxlevel=4,autostyle,german=guillemets]{csquotes}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[style=mla]{biblatex}
\DeclareMultiCiteCommand{\parencites}[\mkbibparens]{\parencite}{\multicitedelim}
\begin{document}
\parencites[cf.][]{key1}{key2}{key3}
\end{document}
Best Answer
U+200B is zero width space which you have here:
from the end of this line
is (using this unicode converter)
delete that line and re-type without the invisible control characters between the
m
and}