How do I change a junk mail to not junk? Somehow my own messages show up as junk mail.

Mark them as not junk. You might need to do that in your mail client, or at your mail provider’s webmail website.

The junk setting can be either because of your own mail client and its spam detection, or your mail provider’s spam detection.

I don’t usually use the BCC-self setting, I just keep the sent copies, so I don’t see usually this.

Your mail messages to them show as junk on their computer?

If so, they need to mark your messages as junk.

Or not, if they consider your mail to be junk, of course.

Senders can’t mark their own mail messages as “not junk”.