All banks are issued a BSB number for each branch from APRA. The ATO validate the BSB number on each return against their master list.
The BSB number that is on the given tax return is not in the BSB number master list.
Search the master list at the following web address: http://www.bsbnumbers.com.
Double check the BSB number. If the client doesn’t able to enter another BSB then please ask to lodge the return without bank details and have the ATO issue a cheque refund.