Thanks for trying to help. the only options I have are 'use the default error address defined for the platform', 'Bounce address' and 'Additional SMTP headers', there is no tickbox to force the encoding or drop down list to select encoding method to be used

I don't see that option in SMTP on delivery properties within Campaign Classic

In my organizations Adobe Campaign Classic environment the character set is different depending on how the proof is triggered. For example if you send a proof by:1) Creating an email delivery, saving then sending using the "send a proof" button in the ribbon the char set is UTF8 2) Checking "Enable ...