[horde] list-mail from new installation

[Ralf]

Hi,

when I send a mail from horde 5.2.10 to the horde list my log said:

status=bounced (host lists.horde.org) said: 501 5.1.7 Bad sender  
address syntax (in reply to MAIL FROM command))

from my old installation (where I subscribed) its ok (like this message).
The idendity is the same.

Whats the problem?

thanks ralf