From Pay.gov, this message could mean a data validation error, this is not a system or transport error.

What this could mean:

Response 4054
- could indicate that that value provided, an account number is invalid or unacceptable based on pay.gov's rules.
- the account number does not match what pay.gov expects for the selected form or payment method
- the account number is not recognized or is not allowed for that transaction type
 

Common fix for a Response 4054
Check for the following:
- Numeric account numbers (no spaces, dashes)
- No masking (*****12345)
 

When the above mentioned all checks out, connect with pay.gov with all the information from the response.
- ID of the error (Ref ID when applicable)
- Full Response 4054 text
- The account number used