🧾 What does the error "Warning! Invalid – Date cannot be earlier than the last document in this sequence" mean?

The Portuguese Tax Authority requires that the issuance of each type of document within a sequence follows a sequential and chronological order, so it is not possible to issue documents of the same type in a sequence with a date earlier than the date of the last document of that type issued in the sequence.

Even if the document is canceled or voided (for example, in the case of invoices, through a credit note), its date is still considered for this purpose.

In any case, there is a solution: simply create a new invoice sequence and issue the desired documents with an earlier date in this new sequence.

You can find all the steps to create a new sequence here.