Are you sure the username is correct ? 
I can't find any record of an account with that name 
    
If it was from 2015, and you had been inactive it may have been deleted. I remember that there was a massive account deletion to free up memory. Maybe yours was one of them.   
Cleaning up [Account Deletion] part 1   
    
the list of deletes accounts -> list   
and as Lorddeath mentioned, he played till johto, so this wipe didn't effect him :)   
Then it is what Raikou said, misspelled username. Or password  :confused: