In most cases, it'll be very easy to find the source of the issue.
Failed to update the invoice
This is the most common error you can expect to see on the invoice, and it will happen when you try to 'save' the invoice at any given time. Here's some tips:
1. There could be a line item on the invoice with conflicting data.
For example, line items on the invoice might have been configured for particular zones, and you might have added the incorrect line item for the zone allocated to the invoice. Go back to the project and verify the correct zone has been allocated. If you get stuck, talk to your manager about the catalogue configuration.
There is a validation error
1. In most cases, this means that a required field is missing some important information that links back to a project or a job. Examples of this can be the quote reference number, Pulse job or Pulse Project missing.