The main reason for this error is if you are submitting with a billing NPI that is of type 1 and using a business name. Here is the reason.
According to the 5010 EDI format, if the billing NPI is the same as the rendering NPI, then the rendering provider information is left off of the electronic claim. The payer is then to assume that if the rendering provider information is missing that it is the same as the billing provider information. However, if you have a business name going out as the billing provider, the payer cannot properly process this (as a rendering provider needs to be an individual).
How to Fix
Overall, you must submit using the same billing NPI that the payer has on file for you. Keep that in mind when determining how to change your information in Therabill.
Look at what you have under Admin in Therabill. This is the default billing provider that will go out on your claims. If the NPI that you have entered there is a type 1 (individual) NPI, then make sure you correctly have it marked as a type 1 NPI.
If you have a type 2 (organizational) NPI for your business and the type 2 NPI is the NPI that the payers have on file for you, then make sure that you have the type 2 NPI entered here.
IMPORTANT NOTE: If you are using Groups or Insurance Company Specific Billing Provider Info to change your NPI on the claims, then instead of looking under Admin for this information, please look under the appropriate section (Groups or Insurance Company Specific Billing Provider).