The log file on the client is located in one of 3 places on the images computer depending on when the log is being written during the imaging process (replace "." with C: or X:):

.smartimagersmartimager.log

.SIsmartImager.log

.smartImager.log

At the very bottom of the log, you should see the reason for not joining the domain.

Also, in the console: choose Components | Domains - and then choose your created domain item.

Make sure that the "Domain Controller" field is blank.  Then click Save and Publish your settings.

Additionally, you can also test and debug the issue if you make sure the "Organizational Unit" field is blank as well.  By clearing out this field (and clicking Save and Publishing) you will force the client to try to join the default "computers" OU bucket).

Most of the time, the failure to join the domain is due to credentials.  You can test this by running a WMIC command on the client.

wmic computersystem where name="%computername%" call joindomainorworkgroup AccountOU="OU=Workstations;DC=ExampleDomain;DC=com" fjoinoptions=3 name="ExampleDomain.com" username="(domainUN)" Password="(PW)"

Or you can use a PowerShell script to help find the error:

Add-Computer ComputerName DomainName DomainUser -Reboot