3815660 - Why I get error 500 when trying to upload unused tickets?

I am trying to upload a file of unused tickets for my company using the following path: Administration - Company Admin - Unused Tickets - Import/Export. When I upload the file previously filled in and then click on Process File, I get an error 500. 

I checked all the data in the file and everything is filled in correctly as per article: Error. "Sorry, something went wrong. The server encountered an error and could not complete your request. If you continue to experience problems, please contact your Company Administrator or Help Desk. (Error 500)" when import Unused Ticket

I tried to upload a file of the unused tickets and when I click process file , I get an error 500. , KBA , CON-TRV-ADM-UUT , Unused Tickets , Problem