"Payer ID is invalid for Apex EDI claim submissions" Error in sending claims

This error indicates that the payer ID you have listed is not correct for Apex. 

Payer ID's can vary between different clearinghouses. Clearinghouses can set up their own client facing Payer Id however the claims will still go out on the backend to the payers payer ID (I know, a bit confusing!)

First, double check the Apex payer ID list below to find the correct ID:

Apex Payer List 

You can update the ID by going to Billing > Insurers > Edit. 

Tip: If you are having a hard time locating your payer on the list trying searching with different key words. For example - you may not find Blue Cross Blue Shield of Massachusetts. 
Try searching for BCBS, or MA, or just Massachusetts. This will give you a wider range of results.