One user reported this, I'm not sure why he's getting this? 

The spam service is returning code 4, which means the account is a known spammer. This is based on the email and/or his IP. 

Is he using a VPN by any chance?

Thank you Martin, however that user is not a known spammer, he's a legit human being who isn't on any of the email spam lists. 

Look in the spam defense logs. If his IP or email has a bad score, even if HE is human… his IP or email may have been flagged as bad. You would need to whitelist him in order to register. 

18 hours ago, Randy Calvert said:

Look in the spam defense logs. If his IP or email has a bad score, even if HE is human… his IP or email may have been flagged as bad. You would need to whitelist him in order to register. 

Thank you @Randy Calvert! I looked in the defense log, I can see his four attempts to register over 2 days, and four times he got a response "4", however neither his email nor his IP is recognized by sites like https://cleantalk.org/blacklists

I wish I had more info as to why the response "4" was returned? 

How can I whitelist a user so they can register? 

 

2 hours ago, Jamynee said:

Thank you @Randy Calvert! I looked in the defense log, I can see his four attempts to register over 2 days, and four times he got a response "4", however neither his email nor his IP is recognized by sites like https://cleantalk.org/blacklists

I wish I had more info as to why the response "4" was returned?

Maybe the email/IP aren't on Cleantalk but on another list like https://www.stopforumspam.com/

IPS uses multiple lists to check, and even their own list based on all IPS communities. They won't share how they return a 4 response though, or (real) spammers would have an easier way bypassing their checks.

 

2 hours ago, Jamynee said:

How can I whitelist a user so they can register?

ACP > Members > CONTENT MODERATION > Spam Prevention > Spam Defense Whitelist (button top-right).

 

IPS should probably add the word whitelist to return this page in ACP's live search as currently it's not included.

42 minutes ago, teraßyte said:

IPS uses multiple lists to check, and even their own list based on all IPS communities. They won't share how they return a 4 response though, or (real) spammers would have an easier way bypassing their checks.

Ok I understand, thank you for explaining that. 

43 minutes ago, teraßyte said:

ACP > Members > CONTENT MODERATION > Spam Prevention > Spam Defense Whitelist (button top-right).

IPS should probably add the word whitelist to return this page in ACP's live search as currently it's not included.

Thank you! And yes you're right as I did search in ACP before asking here because I couldn't find it. 

Glad you have what you need there. Indeed whitelist the person if you know them to be genuine members.