Don't forget to enter your Zimbra version in your forum profile.
Howto: GoDaddy UCC cert renewal
I was able to fix this by checking the option "Allow sending email from any address" under account preferences for the user.
Bug 45140 – mailto:// special link with parameters to open only a small compose window
It got CONFIRMED because of popular vote, and there are, laughingly, just 5 votes, so yes, votes seems to be raising attention :-) at least in some cases!