Hi,
I'm trying to send a mail to an email address of this domain ...@carlsberg.mw 
I always get this error:
INVALID_ADDRESS, ERROR_CODE :553, ERROR_CODE :5.7.1 <my Zoho address>: Sender address rejected: not logged in
This happens very often to addresses hosted by 
mx2.africa-online.net IP: 41.190.93.210

Sending to other addresses works well.
Any idea what I can do?

Thanks
Ben