I have a recent contact who I am exchanging emails with,....but even after adding him to my contact list, his emails are routed directly to my TRASH folder. NOT the SPAM, but TRASH. Can't figure this out. His email provider is ymail.com not gmail, but ymail Apparently this is "son of Yahoo" but my yahoo certainly doesn't like him!!!!
Who is you email provider ?
Are you using your web browser to check mail, or , are you using a client (like Outlook, Thunderbird .. ) ?
Do you have it set up in your email where, you have any emails directed to the trash that is similar? I have a few email addresses that I set up that goes directly to the trash and doesn't even collect 200 for going past Go... lol. And, I noticed, that similar addresses get routed there as well, but, a small price to pay for peace.
There is really no reliable way to detect Spam.
Most filters will make a best guess. It is best to check your trash and permanently delete real Spam Manually. Move the good stuff to another folder.
Just having something in your signature can mark your Email as spam, Because it can be seen as a attachment.
Have Fun Everyone.
Theory only works perfect in a vacuum.