==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.3.2
- Deployed with iRedMail Easy or the downloadable installer? downloadable installer
- Linux/BSD distribution name and version: Ubuntu LTS 20.04
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):  MySQL
- Web server (Apache or Nginx): nginx
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Hi,

I am running multiple domains on the server and all pass the mxtoolbox email deliverability test with both DKIM Alignment and Authentication correct

I have one domain which passes Alignment but fails authentication.  I have checked the DNS records, amavisd-new testkeys is correct and the only difference I can find is that in the DKIM Signature shown on the mxtoolbox results there is a space between the 'd=' and the domain name on the failing domain.   All other factors appear to be the same. 

All domains can send and receive email correctly

the amavisd config file appear correct

On the failing domain the DKIM-Signature     v=1; a=rsa-sha256; c=relaxed/simple; d= domain.org.uk; h=content-type:content-type:mime-version :subject:subject:message-id:to:from:from:date:date; s=dkim ...

Note the space after the d=.  I'm speculating that this is causing the DKIM authentication to fail?

On the good domain the DKIM-Signature    v=1; a=rsa-sha256; c=relaxed/simple; d=domain.org.uk; h=content-type:content-type:mime-version:subject:subject :message-id:to:from:from:date:date; s=dkim; .......

That's the only difference I can find!

Help

PS Thankyou for all the work you do on this?  This is the first weirdness I've experienced and I know it's something I've done - I just can't figure it out!