GroundTruth Text labeling tasks failing

I have a text labeling job currently running, but I am getting an alert that many tasks are failing. The realted cloudwatch log error message is:

{"event-name":"HUMAN_TASK_FAILED","event-log-message":"ERROR: Human task failed for line 6."}

The error in the output.manifest is:

"metadata":{"retry-count":1,"failure-reason":"ClientError: Annotation tasks expired.  Probable Reasons are 1) TaskAvailabilityLifetimeInSeconds parameter is too small.  2) Reward is too low for workers to work on the task.  3) If you use a custom html template, your template may be broken.  4) Data (image/video/text) sent for annotation is broken or too big, preventing completion.  5) All workers declined the tasks.","human-annotated":"true"}

But I don't know how to interprete it and can't find any mention of it online, so any help would be greatly appreciated!