Why is my MYOB duplicating the same Invoices numbers after I generate a Invoice in FT.

This can be be a connectivity issue with your MYOB and FT.

The error that the connection has timed out is probably quite accurate.

Unfortunately this happens with only  MYOB and it lets you duplicate and triplicate Invoices hence why it appears like that in your accounting package and will process and push through invoices multiple times without you knowing.

This is because of the way MYOB is built it has a feature in there that allows you to add the Invoice number multiple times Other Accounting packages do not do this and will come u with a error and reject once generated