Sometimes when emailing invoices we get this error message.  Then we have to close EVO and open it back up and try again.  Sometimes it takes 3 or 4 attempts but eventually it works.  The full message is:
 
The parentheses are unbalanced in this expresion:
 
Warn ERR - File:IM.LIB Line:1262
 
There is a fatal problem with the following expression. The problem may have to do with parentheses: Email(9,'MsgList',,",ESMTP, "$repp12345","irepp@dixoncontainer.com"
 

We have this occasionally, but have never had to restart Evo. Just trying again has always worked. We are on Office 2013 though I can't imagine that has anything to do with it...