This error will occur if the upgrade process was not able to update one or more config files. You will need to modify the two files below using a text editor such as notepad.
Hurricane MTA Serveraccounts[account]configgeneral.config
Hurricane MTA Serverconfigaccount_templatesgeneral.config
Open each file and check for the two ini file sections below. If they do not yet exist, simply add them to the bottom of each file. Once you make the changes and save the files, the settings page will start
working without the need to restart any services.
Enabled = False
SuppressFailAtRcptTo = False
SuppressEnableMd5 = False