as requested per issue2551203, here are the requested email messages

the problematic characters dropped into the mail by copy/paste from the devtools browser window.

however, maybe the header line:

    Content-Type: text/plain; charset=UTF-8; format=flowed

should have triggered conversion to utf-8 instead of ascii.

when opening message_to_mailgw.txt in python with ascii codec, you get exactly the same error message:

>>> open ("message_to_mailgw.txt","r",encoding="ascii").read()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python-exec/python3.9/../../../lib/python3.9/encodings/ascii.py", line 26, in decode
    return codecs.ascii_decode(input, self.errors)[0]
UnicodeDecodeError: 'ascii' codec can't decode byte 0xef in position 1817: ordinal not in range(128)


thanks,
marcus.