brute-force with tsgrinder

For those of you who are familiar with TSGRINDER, I would appreciate your help. 

I having trouble compromising my remote machines.  The target devices are on a 
domain. I have the username (Local\Administrator) and typed the current 
password into the dictionary file (Wordlist.txt).  Then open a cmd-line, browse 
to my executable and type the following string:

tsgrinder.exe -w wordlist.txt -b -n 1 -D 8 192.168.x.x

A RDP session opens and attempts the passwords within my dictionary (the 
correct password is third down on my list) but when it trys the right password 
it responds with a "Failed"??

I checked the local administrator account to verify it was not locked out.  Not 
sure what else to try??

Any help is appreciated!

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