Ground Truth - Error loading Image for Task

Hi,

I am creating a custom labeling job using boto3. It creates the job and the user is able to access the job using the front end tool but it does not load the images. I am using the default pre labeling lambda functions (arn:aws:lambda:us-east-1:432418664414:function:PRE-SemanticSegmentation) and the default for the annotation consolidation lambda (arn:aws:lambda:us-east-1:432418664414:function:ACS-SemanticSegmentation). I think the issue is with the name I am using for the LabelAttributeName (custom-ref) but I am not sure.

Full error: There was an error loading the image for the task
This task was created incorrectly and cannot be completed at this time. Please return/stop this task.

Any help would be appreciated.

Thanks,
Humberto