I am pretty sure that there are dozens of entries here that probably explain this. First, it is always helpful to provide the model type quintum.
If you have a gen 1 product or your gen 2 product is at P103 or higher, you can reset the unit to factory default, erasing the entire configuration including the password, but not the IP address. You do this from the boot up menu with direct connection to console port.
If you have gen 2 product that is less than P103, you will need to contact quintum directly to change this.