A very old reason for that behaviour is if the \id lines at the very top of the file get edited and no longer match. This line identifies the file and if it is changed them paratext biblical terms tool can’t find the verses in that book.
Do a find on \id with show text ticked and all books selected. The line should look like this in every book
\id MAT - Project name
The MAT must be the three letter book code that Paratext uses to identify the book. You see it at the top menu line when you select which book you want to edit. Teams sometimes translate that into their own language, putting something like Matiyu instead. This
is wrong.
The project name must match the long project name that you see in the project properties and settings menu. Teams often change this too. If they wish to change this (a legitimate change may be from Language Name NT to Language Name Bible), they should change
it in project properties first.
Then do your find and make sure that every \id line exactly matches the others, differing only in using the proper book code and with the project name matching the project properties project name.
After that, the biblical terms tool should work as expected.
Blessings Shegnada