Redmine

My redmine installation is configured to recieve e-mail.

When i try to create a new issue on unspecified project redmine answer is:

Request was denied by your Redmine server. Possible reasons: email is sent from an invalid email address or is missing some information.

but in file log

MailHandler: missing information from Francesco: Unable to determine target project

Same result for missing required field

Validation failed: Categoria non può essere lasciato in bianco

(Category cannot be blank).