Sender verify failed for legitimate hosts


Well-Known Member
Jan 2, 2006
Just had a customer saying that they are not receiving mail.

I sent them a test message from an address at our domain and received a bounce "Sender verify failed" this is also reflected in the exim log. The problem is not with our domain.

I have done /scripts/eximup --force and also removed sender verify and callout tick boxes in exim config whm. I've cleared out the advanced section - then added sender verify back.

Problem still happening. Any ideas ?


My bounced message is actually saying this...

550-Response: 550 Sender is Blacklisted
550 Sender verify failed

The exim log simply says sender verify failed.

The sending server's ip is not blacklisted.

Heres what I have in the exim config on the target server...

accept hosts = :

drop dnslists = :\
message= Sender is Blacklisted
!hosts = +relay_hosts
!authenticated = *

# Accept bounces to lists even if callbacks or other checks would fail

Edit - target domain is on a dedicated IP - would this make any diff ? (dont think so)

Note: If I remove the sender verify options - mail gets through ok. We have had no complaints form other users on this server that they are not receving mail.
Last edited:


Well-Known Member
Aug 6, 2006
check if your clients ips blocklisted on spamcop .

Did you enable the boxtrapper ? disable it

The email id from where you are sending mails are created in cpanel , right ? .

Restart the exim service and check again .


Well-Known Member
Jul 21, 2003

The problem could be that the sender server doesn't answer your request. I read your other post regarding callout. No matter how long do you set callout, the other server doesn't give an answer.
The most common problem with sender verification fails are some servers that refuses to verify senders address. You may whitelist those senders if this situation only happens with certain senders.
Here is a thread that shows you how.

Also you may set callout to a lower number, you don't want your server wait 300sec for an answer that should be in fractions of a second. You may tweak this by setting a lower number or leave the 30secs by default and add defer_ok. So if an answer is not received, you accept incoming transfer.