I dont know, if my question has been posted, so I will try now once more.
Trying to import the test file (taken from the “Documentation”), there nothing happens, it shows the empty wordpress page with “Import” in the header.
We have checked the CSV in documentation page and did a test import in our test environment. The CSV has successfully imported with no issues. You may please export coupons from your site and you can use it as a sample CSV for reference.