Yes, in Kindle the address is unblocked, I can sent to my device from my normal e-mail address and other adresses I listed earlier without problems. Just from Calibre they are refused.
I believe Calibre is supposed to send e-mails in the name of my own e-mail, but perhaps the systems (my e-mail provider, Amazon, etc) recognise the e-mail as being sent from an unregistered e-mail address?
How do I tell my security software to ignore or accept Calibre e-mails? Don't I need to know under which name or from which address or server Calibre sends its mails?