in older UTM versions, when I tried to release a mail already released earlier, there was a error message stating the mail cannot be found and this is probably because it already had been released.
In UTM 9.185 I get this message:
Please provide a password to encrypt the e-mail message that you want to send to the %%RECIPIENT%%. Your e-mail was not sent to the recipien.
Also note the last word has a spelling mistake.
Regards,
Bastian