When the voucher numbering method in your voucher is not set to automatic, this error occurs. Read on for the solution.
The entries of banking are posted into payment, receipt and contra vouchers. If, the voucher numbering method of these vouchers is set to "Manual" or "Automatic (Manual Override) or any other method other than "Automatic", this error will occur: "Voucher Number cannot be left blank".
To check the reason of entry fail kindly refer here.
To resolve this, simply go to your "Payment", "Receipt" & "Contra" vouchers in master alter and set the voucher numbering method to "Automatic".
After setting the method to "Automatic" in all three vouchers i.e. payment, receipt and contra you are good to go. Simple again send the data to tally from Suvit.