I have been having some issues with my EC sales list submission. It worked fine in the past but suddenly the VAT submission went fine while the EC sales list was refused with “Authentication Failure. The supplied user credentials failed validation for the requested service.”

I then proceeded to try it manually using the CSV (as the rest of the submission had already been accepted) but that failed too. This way did provide more detailed error descriptions which are probably the same reason the automatic submission was refused.

The exported CSV:

1. Contains the full VAT number GBXXX XXXX XX of my company whereas the upload tool requires the country identifier and spaces to be removed. I can't remove the country ID from my VAT number as I have customers who require that to be on my invoices. I suggest stripping country ID and spaces from the Kashflow user's VAT number before the submission or export to CSV.
2. The branch identifier can not be ‘0’, it needs to be a three digit code. ‘000’ works fine. On the page https://www.kashflow.com/support/kb/vat-submission-errors/ you suggest ‘0’ so perhaps change that advice to ‘000’ as well. Perhaps even automatically convert it for users that currently use '0'.
   
3. It does not strip the country identifier from my customer’s VAT number. The first column should contain the country ID, the second column the VAT number stripped of country ID and spaces. Customer number NLXXXXXXXXXB01 should be converted to NL,XXXXXXXXXB01 before it is exported to the CSV.
4. The amount of the sale to that customer should be in whole numbers, no decimal point or pence/cents. I suggest rounding it up or down to the nearest number before feeding it to the HMRC API or the CSV.

I hope this helps the developers fix these issues and anyone suffering from the same problem in the mean time.