OT - Help with resulting error message

[Steve Campbell]

Glenn Steen wrote:
> 2009/6/3 Steve Campbell <campbell at cnpapers.com>:
>   
>> One of our users is trying to email users at a particular domain and is
>> receiving the following error message back from them:
>>
>> (reason: 550 5.7.1 rejected content, black listed twitter.com by
>> multi.surbl.org #762 #895 (l51Ehj043192426600))
>>
>> I asked if he was posting through twitter, and he said he was not. I checked
>> SURBL and our IPs are not listed. So I'm confused(as always) by what this is
>> telling me. He does have a reference to his twitter stuff in his signature.
>> Do any of the SURBL lists really block content?
>>
>> A good explanation would be helpful. Thanks much
>>
>> Steve Campbell
>>
>>     
> Are you sure he used your servers to send that? Not gmail or somesuch?
> If he sent it through your servers, you should be able to find some
> log entries on your box(es)... Might shed some light on things:-)
>
>   
Pretty sure. The log entry for one of the emails just states that the 
"stat=Service unavailable", which is likely the result of the 550.

Thanks Glenn