Report upload error: "Report type not supported" with apparently correct TR report

Overview:

Brill TR can't be manually uploaded and stored in the system, "report type not supported".
The report was downloaded from the provider's website. Is there an error in the CSV report or in our upload functionality?

Steps to Reproduce:

1. Log into some FOLIO environment (Iris & current snapshot)
2. Go to eUsage, some UDB
3. Upload the report attached to this issue (Brill TR)

Expected Results: 

Report uploads and is stored in the system.

Actual Results:

The report is uploaded, but is not parsed.
Error message:

Failed... Error saving report: org.folio.rest.impl.CounterReportAPI$ReportUploadException: org.folio.rest.util.UploadHelper$FileUploadException: Wrong format supplied: Report type not supported

Additional Information:
I checked the report header and attributes, but didn't find anything unusual. 
I tried to add metric types (as none were listed), but the problem stayed the same.