mail is calling good messages junk

yeah - as Barney has said - this is one of those issues that will be very hard to fix. The best you can do are

• inform the person sending the mail, there are things they can do to improve their reputation
• you might have a spam filter at server level (before it comes to your computer) where you might be able to log in and mark the email as Ham (ie not SPAM). This is only for more specialist providers though.
• You could contact your email provider and ask them to flag that that sender is not SPAM, but unless you have a specialist email (ie a business address with a person who administers it) or very, very helpful provider you probs won't get far with that

Generally the impetus is for the sender to improve their sending reputation. The best you can do is mark them as not junk and hope that feeds into the ether somewhere.

Brady Nations wrote:

Yes, there is an x-spam header. Why would it be suspected spam when it's a reply to a message I sent to someone in my Contacts?

Because a message can go through thousands of mail exchangers on its way to your recipient and also back to you. Any one of them can decide it looks like spam and add the header.

Go to View menu, Message > All Headers.

See if there is an X-spam header.

By default, the Junk email filter is set to trust junk email headers.