Why is my Xero invoice failing to create when a contact has multiple email addresses?

If you use Xero and see:

“Failed to create contact in Xero: Email address must be valid.”

the first email address on the SortScape contact is not a valid address. SortScape can store several comma-separated email addresses on a contact, but Xero only takes one email per contact, so SortScape sends the first address as the Xero contact’s email. Extra addresses no longer cause this error on their own.

How to fix it

1. Edit the contact in SortScape.
2. Check the first email address (before the first comma) and correct it.
3. Create the invoice again.

How the other addresses reach Xero is covered in Contacts with more than one email address.