Fortinet 124E Firmware Downgrade

I am in process of downgrading a firmware of 124E however encountering following error when trying to do so: 

""Downgrade Warning

Some incompatible administrator accounts were found with FortiSwitchOS versions<7.0.0.

if desired, convert incompatible accounts using the "execute system admin account-convert <admin>" command

Unconverted accounts will not be able to log in with FortiSwitchOS versions < 7.0.0.""

I executed the the command multiple times then it prompts for New Password then I am unable to type anything in CLI. 

Current BIOS Version: 04000008

Firmware Version: v7.2.5.build0453.230707 (GA)

Trying to downgrade to: FSW_124E-v7-build0444-FORTINET.out