Change default from address

I created a simple workflow using designer to send email.

but the workflow keep error on send mail = "there is no connection string for the destination email address system@k2local"

I already

- add on ConnectionStringEditor.exe  "sourcecode.net.mail.smtpconnection" with my gmail configuration smtp

- change on "Management>Environment Library> Development" and "Management>Environment Library> production", From address value with my email.

- Update File K2HostServer.exe.config sendmailfrom with my smtp mail address

but the error keep about system@k2local.

Please Advise.

Regards