On Development Server

When I use Mail API with sendmail using the example as in Sending Mail doc, the recipient has to be pure email address:
cannot be
User <user@example.com>
Or sendmail complains:
INFO     2008-10-29 06:57:53,884 mail_stub.py] MailService.Send
INFO     2008-10-29 06:57:53,884 mail_stub.py]   From: support@example.com
INFO     2008-10-29 06:57:53,885 mail_stub.py]   To: User <user@example.com>
INFO     2008-10-29 06:57:53,885 mail_stub.py]   Subject: Your account has been approved
INFO     2008-10-29 06:57:53,885 mail_stub.py]   Body:
INFO     2008-10-29 06:57:53,885 mail_stub.py]     Content-type: text/plain
INFO     2008-10-29 06:57:53,885 mail_stub.py]     Data length: 261
/bin/sh: -c: line 0: syntax error near unexpected token `newline'
/bin/sh: -c: line 0: `sendmail User <user@example.com>'
ERROR    2008-10-29 06:57:53,927 mail_stub.py] Error sending mail using sendmail: [Errno 32] Broken pipe
I think this can be fixed by patching the mail_stub.py.

On Production Server

Sender must be:
The sender must be the email address of a registered administrator for the application, or the address of the current signed-in user.