Sorry for the late answer, I should press the "keep me updated" button:
go into site.ini line ~576 you'll see:
# The line endings used for headers in mail messages. If you need to use
# control characters like LF or CR you need to use it's urlencoded value, for
# example %0A for LF and %0D for CR. The default setting is what RFC 2045
# requires: CRLF
HeaderLineEnding=%0D%0A
