SMG "request exceeds the limit size."

hi all,

we are using SMG version 10.5.4-4.

There is a message in spam quarantine whitch is not actually a spam. when I select mssage and click to This is Not a Spam. SMG gives me following message

"Cannot submit the selected message(s) to Symantec Security Response. The request cannot be processed because request exceeds the limit size...."

I have already changed the MTA limit size in "Administration - Configuration - SMTP - Advanced Settings... and configure the message size limitations."

but nothing has changed.

could you please give me some advise