Explanation
According to the Salesforce Help article on Understand and Troubleshoot Unit Assignment in Salesforce Maps Territory Planning5, two steps that a consultant can take to troubleshoot the issue of no units assigned to areas are: edit the data set, and see what field was used for Unit Assignment, and create a new alignment, and use the correct matching logic for this field; and edit the data set, and what report and/or queries were used to create it, and double check that the reports and/or queries return records when logged in as the OAuth user5. These steps will help ensure that the data set has valid unit assignment values and that there are no issues with data access or permissions5.