Why can't the reviewers review/prereview the assigned abstracts?

In case the reviewer has an abstract assigned and they can see it but they are not able to review you must check the following

• Reviewing dates
  • Review start date: This is the date were reviewers are able to start scoring, if this date has not arrived yet the reviewer will not be able to review
  • Review end date: This is the date until were reviewer is able to score, if this date has passed the reviewer will not be able to review (Please Note that the reviewing process is going to be close at this date at 00:00, so this must be setup with an additional day of the due date)
• Reviewer must have the enable to review check

You can find this on the Reviewer View > Filtering by Not allowed to review 

Then you can bulk update with the update options at the of the page, also you can open the individual by clicking the ID Column number, on this new screen you can see the option for allow to review.

• If the reviewer has a duplicate record with the same email it must cause that is not enabled if any of the records have this option unchecked. We suggest that every reviewer has a unique email.