An invalid reference warning may appear in the Sections & Passages tab.
Warnings have two parts:
There is a colored banner at the top of the table with information.
One or more cells in the Reference column will be highlighted with a colored background.
Audio Project Manager identified a reference that will not sync correctly with Paratext.
Examples:
An incomplete or missing reference.
A break in the middle a verse was not entered correctly.
Spreadsheet convention mentions you must use lower case letters and hyphens.
An En dash or Em dash was used instead of a hyphen.
A reference that spans chapters that was not entered correctly, such as spaces.
You need to complete or edit the passages so the reference can sync with Paratext.
You will probably want to update any spreadsheet you copied and pasted.