I have had the same issue with CLIA numbers and multiple line claims. If you want to bill single line claims you can put the CLIA number in the prior authorization box in the claim information part of the form. DO NOT put it in the prior authorization box in the Line information. I have had numerous claims paid by doing so.
According to what I have discovered the error occurs on the Availity site when you have more than one claim line. Every multiple line claim that I have filled out has been rejected by Availity and Healthy Blue never receives the claim submitted.
I have talked to both Healthy Blue and Availity about the issue. They said they were looking into the issue and trying to figure out how to fix it.