The addOptionalArguments method throws an InvalidArgumentException if an argument contains exclusively non-ascii characters.

e.g. if the traderName is ΕΛΛΑΣ

– note that the E and the A are Greek, and not Latin, unicode characters here. For test purposes something like Äß also throws the exception.

The filterArgument strips away all greek letters (and accented characters such as ä and é). In the case of ΕΛΛΑΣ – this means an empty string is sent to validateArgument.

The regex in validateArgument is probably also problematic. Changing to this:

/^[a-zA-Z0-9α-ωΑ-Ω\s\.\-,]+$/

– Will allow the greek alphabet but I don’t know whether that’s sufficient.