Not Able to enable DKIM in Office365 - Online Exchange server

I have been trying to enable DKIM on office365 since a couple of days. I have entered all the require CNAME entry in the DNS. But when I try to run the below command via Powershell Ran Powershel...

harveer singh
Aug 22, 2020
Hey Sumesh1980 ,

Okay, Just tested it, it appears you did not run the command :
New-DkimSigningConfig -DomainName <domain> -Enabled $false before updating the CNAME records.

So here are the steps that you need to complete in order to get this working:
1. New-DkimSigningConfig -DomainName <domain> -Enabled $false
2. Get-DkimSigningConfig -Identity <domain> | Format-List Selector1CNAME, Selector2CNAME

Grab the CNAMES and update them in DNS.
Then run the command:
Set-DkimSigningConfig -Identity <domain> -Enabled $true

After running the command in Step 1, it should not give you the domain not found error.

Thanks

harveer singh

Steel Contributor

Aug 22, 2020

Sumesh1980

It depends on the DNS you are using and there may be a delay but most of the times it is not actually the DNS rather incorrectly updated records. The common mistake is to end up updating domain name twice like for example :

selector1._domainkey.domain.com.domain.com is updated as the CNAME instead of simply selector1._domainkey.domain.com.

Please follow instructions related to your DNS provider only to update the records. See this case in older post:

https://techcommunity.microsoft.com/t5/exchange/unable-to-activate-dkim/m-p/1540512

Thanks