What are XNOTES?

Hi Martin,
<the problems are solved. 
Really.  You are spreading bad info.
See the response today from SM support:

Hello Everyone, 

Thanks for all your posts, everyone. For majority of our customers, the DKIM issues with outbound messages have been resolved. We are aware of a lingering issue regarding implementation with Declude. It appears that when Declude adds X-Notes headers to an email, DKIM signing fails on outbound messages. (X-Notes are extra headers and fields added to an email to show a message. You can use X-Notes to put say an abuse email address into an email's raw content.) This information was forwarded to the development team, and they will be working to get this fixed. 

Best Regards, 

Hi all, 

We found that this DKIM issue was caused by the handling of repeating header fields in the email. This has been resolved in Build 7858: 

We appreciate your patience as we worked through this.

UPDATE: 

I wanted to post this here in case anyone else runs into a similar problem. After our fix in Build 7858, Nick was seeing lingering DKIM failures when emailing Gmail. Upon further review, we found that Gmail does not accept DKIM with any key size lower than 1024. This issue was resolved by modifying the key size.

If any of you find that only Gmail is failing DKIM signing, please check your SmarterMail's DKIM settings to ensure your key size is at 1024 or higher.

I have to say having a support contract is the way to go.  SM support will resolve an issue without question... Thank you.

@Zach Sylvester we're having issues now sending email to Gmail. Updated to the latest SM build today. I deleted  the DKIM  key and added it back again and it's 1024 size. It says it's running, but all @Gmail.com email is getting rejected.

We also use Declude.

@ActorMike, I recommend that you open a support ticket.

Actually, I did yesterday and even did an RSAA but got a vague response back from support, so I closed the ticket andI figured it out on my side. Turns out, Google recently started blocking email that contains bit.ly links generating this same error. Here is a blog with more details- https://websiteworld.com/gmail-delivery-delayed-remote-server-returned-421-4-7-0/

This might be helpful info for your team. It appears that today was the first day Bit.ly was aware of the issue themselves according to a reply to my tweet this morning.

Thank you for that information.  I have passed the information to both the dev and support teams.