Why am I unable to generate an einvoice for a different state in BUSY even after entering the correct GST number and pincode?

If you are not able to generate an e-invoice for a different state in BUSY even after entering the correct GST number and pincode it may be several reasons,you may check these things:
 Step 1:You can sale type, if you and your party is from another states so igst should required so you can change your sale type as igst.
 Step 2:If party is another state but your goods will be ship on local state and you wants to apply local tax on your invoice, so you will need to enable billing and shipping in your BUSY.
 Step 3: Go to Administration menu,
 Step 4: Select Configuration,
 Step 5: Select voucher series configuration,
 Step 6: Click on sales select series and open voucher configuration tab,here is a option enable billing shipping details then specify Y then save. 
 Step 7: After that while generating e invoice you will see there after selecting a party,Billing shipping window will appear, you need to select GST report basis as per billing shipping in the billing shipping window. You should also mention the local address in it, then click generate automatic here you will see the option is pick place of supply from billing shipping Details specify Y Then proceed to generate it will be generated successfully.