reset the password on a Dell PowerConnect M6220

Hello, I am trying to reset the password on a Dell PowerConnect M6220.  I can login to the CMC via the https webpage but dont see how to do it from there. 

So I am trying to plug in a USB serial cable into the console port and reset the password via a console session using teraterm but when i do this all i get is a blank screen. 

Serial settings are:

Cable: Null Modem

Bits per second: 115200

Data bits: 8

Parity: None

Stop bits: 1

Flow control: None

Any ideas on how i can access telnet access to the device to reset the pwd successfully

thanks

Kevin