132 - Entity's Medicaid provider id. Usage: This code requires use of an Entity Code.

The payer is indicating that either the NPI that you entered for the billing provider or rendering provider is not an NPI that they have on file.  It could also be that this provider is requiring a legacy ID.  A legacy ID dates back prior to the NPI mandate when payers would assign their own ID for each provider.  A legacy ID is not normally required on claims since the NPI mandate, therefore, more than likely they are referring to the NPI.

Rendering Provider or Billing Provider?

Unfortunately, their rejection message is not indicating if they are referring to the billing provider ID or the rendering provider ID.  More than likely, they are referring to the billing provider ID.  However, you may want to call the payer to find out exactly why they are rejecting.  Remember, when calling the payer, you will want to let them know up front that you submitted electronically and your claim was rejected by their EDI department.

Where do I fix this in Therabill?

Billing Provider:  By default, Therabill will use the information you have under Admin -> Member Info as your billing provider information on the claim form.  However, there are ways in Therabill for you to change the billing provider information for specific providers and for specific insurance companies.  At the top right of your Member Info page (click Admin in the top navigation bar of Therabill and then click on Member Info in the drop down), click the link labeled View All Billing Providers to see a list of where Therabill will be pulling billing provider information for you in various cases.

Rendering Provider: This information is pulled from Providers->Provider List in Therabill.  These are your therapists.  IMPORTANT:  If the rendering provider NPI is the same as the billing provider NPI, according to EDI standards, the rendering provider loop is to be left off of the EDI claim and the receiver (the payer) is to assume the rendering provider information is the same as the billing provider information.