Does anyone @UPC happen to know what this means:

host mx.hispeed.ch [213.46.255.2]: 552 5.2.0 rl4b1r00p3kCCMl01l4bgK automated process detected unsolicited content

The email is being sent from a UPC connection, via Hostpoint (mail.hostpoint.ch) to a user @swissonline.ch.

The user has tried getting an explanation from UPC, but sofar no luck.