Weird things in the mail queue

[Aki Tuomi]

On 21.2.2019 13.47, Lionel Elie Mamane via dovecot wrote:
> I noticed a mail stuck in my mail queue. dovecot-lda was returning
> error 64 Invalid parameter given. (EX_USAGE).
>
> Weird, weird, weird. After some sleuthing, I found the sender address
> was FirstLast at domain.tld, with a UTF8-encoded Unicode U+FEFF ZERO
> WIDTH NO-BREAK SPACE character (AKA byte order mark) between "First"
> and "Last" :)
>
> Since that is passed as the -f parameter to dovecot-lda, it was giving
> the 64 error.

Your MTA should not be passing this along.

Aki