The message with the VM error code is from VM's outbound mail servers which have blocked the sending of the mail because the VM servers with the help of the filtering provided by Cloudmark (your spam filtering partners) thinks it is spam or contains spam content.
If it has been blocked on receipt by another ISP the message would have been completely and utterly different and not had the VM 603 code attached.
As a Very Insightful Person, I'm here to share my knowledge. I don't work for Virgin Media.
I am getting the same problem please tell me the finest solution for the problem. Also my soundcloud is not working very good. Crashing at random point of time.
Your problem needs to be addressed in a new thread. Please repost with the exact error message including any string of characters which identifies the exact transaction to the the forum team who can correlate the codewith their logs to see what text triggered the spam content warning.
But do be sure to delete any personal email address or suchlike.