Cannot import csv file of lists from other install ("There was an error on the backup")

Situation
Running multiple instances of OpenEMR. Have customised a set of lists on one server and want to import these to new server. Have created backup of these lists using Admin>System>Backup>Export Configuration (lists.csv). Trying to import this file (Admin>System>Backup>Import Configuration) results in immediate “There was an error on the backup”.

OpenEMR Version
I’m using OpenEMR version 6.1

Browser:
I’m using: Microsoft Edge

Operating System
I’m using: Win11

Logs
Checked logs, no relevant entries.

Turns out to be deep technical issue specific to our server setup - Mods please delete thread. Apologies.