IP address listed as spammer

[scpgsm_rnd02]

Some of my web visitor complain when their trying to create account in our forum appear this messages :
"Sorry, but your IP Address has been listed as a known spammer. You will not be allowed to register."
when i am trying to create account from my computer,..
this messages is appear too
i am browsing for this problem in forum, an found that disabling user banning option can fix this problem..
But this messages are still appear...
What should i do fix this ?

Any suggestion are welcome..
thanks..

[beishe8]

Probably a modification is causing this.
Disable all the mods and try to register to your forum.

[Trevor Hannant]

As per your ticket, that phrase doesn't exist in a default installation. Do you have any anti-spam modifications installed?