Hardware: Mu-4000 , Mu-80x0
Then reboot the Appliance and try to access it from browser again. If this Does not fix the issue, Please console Into the Mu Appliance and follow the below suggested steps. The console setting are as follows,
For Mu 80x0
Speed (Baud rate) : 115200 b/s,
Data Bits : 8
Stop Bits : 1
no parity or flow control
For Mu 4000
Speed (Baud rate) : 9600 b/s,
This makes the device accessible via GUI. Now you would pass those pages and reach the login page. The Mu Appliance will be set back to 5.5 version and all the data will be lost. We could always to a offline update and bring it to the latest version and then restore the backed up data.