I forgot to mention, that I create a record "mail.thread", because I want to save the E-Mails in Inbox. I no attachment is there, it works with mail.thread record. But if there is an attachment in the E-Mail, then the error comes.
I forgot to mention, that I create a record "mail.thread", because I want to save the E-Mails in Inbox. I no attachment is there, it works with mail.thread record. But if there is an attachment in the E-Mail, then the error comes.