Just as a note for [email] mailtag Syntax errors ONLY showing on the autoresponder ‘Mail(2)’ part of the mail setup tab/page.
I was somehow using [text* UserEmail id:UserEmail] (please note the use of [text*] NOT [email*]) as my forms Email field and this was causing the above ‘Syntax Error’.
It did NOT find an issue when using the {UserEmail] (text* type) in the ‘REPLY TO:’ field however, and this caused me a bit of searching to fix.
Hopefully this helps someone.