Thanks for posting on the reckon community.
when you are using the hosted standard, you are using remote desktop connection to log into the hosted environment.
when you are using the hosted premium, you are using citrix receiver to log into the hosted environment.
the reason why you may not be able to fax from the hosted premium is because the citrix receiver may not be compatible with the fax feature of this brother MFC printer.
you may need to contact your printer manufacture to see if you can get a driver that is compatible with the citrix receiver to enable you to fax from your brother printer. alternatively you may need to contact citrix to find out if there are specific configurations to enable citrix to be able to fax from this printer.