Unable to Upload Blacklist

Issue:

Unable to successfully upload a blacklist file through the NexOSS user interface. Receiving “Operation failed” error returned during blacklist file upload attempt.

Log message:

Operation failed:
Code definition must be unique. Check code "00_)*+?[$????**????????". it is defined at least twice "????????" and "????????"
Please go back and try again.

Solution:

Save the Excel spreadsheet as a tab-delimited-txt file first, then use the Browse/Upload from the Configuration/Upload page.