The KB article here may help in providing the relevant data to support.

The table tblErrorLog typically holds any errors that occur but not always, e.g if your transaction log is full and the DUJ is stopped mid processing. Check the following if you haven't already done so...

select * from SnowLicenseManager.dbo.tblErrorLog order by LogDate desc

Review the Message column of the following query might give you an idea where the job stopped...

select * from SnowLicenseManager.dbo.tblJobLog order by ActionStart asc

...but it looks like you may have checked this already and found them to be blank?

If you wish to get your DUJ running again, you can reset the relevant tables using the following script (taken from this article)...

--Step 1: Stop the job if necessary

USE msdb

GO

EXEC dbo.sp_stop_job

N'License Manager Data Update'

--Step 2: Update Job Status

USE SnowLicenseManager

UPDATE tblJobStatus SET LastJobStatus = 'Job finished successfully'

--Step 3: Update the log

UPDATE tblJobLog SET Message = 'Job finished successfully' WHERE JobType = 'JOB_RUN'

--Step 4: New Step for SLM 9 (DUJ 2.0): Zeroing out the temp tables

UPDATE inv.tblJobParallelStep set [Status] = 0 where Status= -1

--Step 5: Update System Info table (note this is needed to tell IIS to allow access to the SLM)

UPDATE tblSystemInfo SET LastJobStatus = 'Job finished successfully'