SmarterMail isn't signing outgoing mail for me either, even though I've gone through the DKIM setup process. It's never worked for me actually, but I'm a new user--I started with version 16.3.6535 since it was the latest version when I bought SM, and I'm on 16.3.6551 now, which is the latest version as of this writing. I switched from a different mail server product, with which DKIM signing was working properly. Like yours, mine also says "DKIM is running on this domain and signing outgoing mail.", and I believe I've created the correct DNS entries (the DKIM setup in SmarterMail verified them), but test messages that I've sent to other servers don't have anything about DKIM in the headers, and a couple of DKIM testing sites I found tell me that the test messages they received from my server didn't have a DKIM signature at all.

 

Regarding your last sentence, unfortunately I can't add any evidence about whether or not the change from 6530 to 6535 may have had anything to do with it since I only started on 6535, but I wonder if a bug may have been introduced there.

I`ve been experiencing the same on Version: 16.3.6474

I ran into this too.  It seems after going from version 14 to 16 the DKIM broke.  It seems in this version SmarterMail creates a new DNS entry.  I have to update all my DNS records for the accounts I had.  Before I used: secure._domainKey.domainname.com, now it seems and probably a good thing generates a unique key name, now it is something like 123456789._domainKey.domainname.com.  I would disable it if enabled, then enable it.  I have only seen I can view the key and name one time, so I am making a copy.  Update my DNS records.  I use the 1024 key I have not figured out how 2048 in BIND.  The records (notes this for BIND) I use and I pass Google's tests:

 

_domainkey.domainname.com    IN    TXT    "o=~;"

123456789._domainKey.domainname.com    IN    TXT    "k=rsa; key provided"

_adsp._domainkey.domainname.com    IN    TXT    "dkim=all"

 

I also have a DMARC record

_dmarc.domainname.com    IN    TXT    "v=DMARC1; p=reject; rua=mailto:postmaster@domainname.com"

 

I also have an SPF record.

 

These all seem to give me three thumbs up on Gmail's security.

 

16.3.6558 Still not signing for me (according to mailtest@unlocktheinbox.com)

That did work, however:

When I open the domain settings general tab, I see the message that "DKIM is running on this domain and signing outgoing mail.", and when I look at the record, it matches the record in DNS. There is no clue that the private key has been whacked, or that I should reconfigure DKIM setup.

 

After I click disable, when I click enable again, I get the record display. When I click close, DKIM Is not enabled, I have to enable it a second time.

Hi Sergey. Would you please try upgrading your mail server to the latest release? There have been some fixes to DKIM since your minor version:

 

"Fixed: DKIM headers fields can be erroneously set to null or a zero-length array causing NullReference exceptions." (16.3.6733)

"Fixed: DKIM email signing uses non-FIPS compliant algorithms." (16.3.6691)

"Fixed: Improperly folding in the DKIM signature causes it to fail." (16.3.6670)

"Fixed: In some instances, system messages, such as specific types of bounce messages, are not being DKIM signed and, therefore, get sent to Spam Folders." (16.3.6649)