Good mail diverted to Junk folder with Junk filtering off

I have been a happy SpamSieve user for multiple years. Thanks for this great product.
For some reason, it seems as if I see a new and unwanted behavior on my office iMac. I am not sure exactly when it began.
Background. I use Apple Mail, MacOS 10.12.4, Mail version 10.3 (3273).
The issue: I am seeing multiple good emails getting diverted to the Junk mail folder. I have the SpamSieve rule set up as I have for years, Enable junk mail filtering is off. Yet I see a good deal of email going into a Junk folder. Some of these messages are mass produced, but I would like to see them, e.g. Williams Sonoma or other merchants. Some come from lists I subscribe to and get via email, e.g. Nextdoor. Is the email getting diverted at a server level. I use multiple email accounts and all seem affected. Let me know if you want the domains, if that makes a difference. A few messages go into the Spam folder I set up, and I curate them as needed. I do not that it seems that a high percentage of good messages end in the Spam filter.
I have identified the mail manually as “good” many times, marked it as not junk, dragged it to my Inbox, then marked “not junk” and “good.”
I am frustrated by this behavior. Should I do a massive reset on SpamSieve and start over with the filtering? My stats began in 2006, so one thought is that something has just gone out of whack. The stats say I literally have thousands of blacklist and whitelist rules. If it would be helpful to see stats, I can send a screen shot. On the stats, it shows 48% false negatives.
I have had to go through my Junk folder every day to retrieve messages I should be getting normally.
Please advise of what I should do.
Many thanks.

z_owner

Yes, most likely this is because of a server junk filter. Please see this page.

The messages were not even examined by SpamSieve because the server filter caught them before they got to your Mac. So they do not need to be trained as good.

No, that wouldn’t help because SpamSieve is not what’s catching those messages as spam.

Thanks very much. You confirmed what it appeared from my review of your manual. Now the hard part. I now have determined that the offending server is sbcglobal.net, part of the ATT system. After some research about how to turn off the Spam filter, I spent some time trying to get to the Settings and failed. I logged on their web mail, but was unable to select Settings at all. If you have any insights or experience with them, let me know.
I may have to call ATT.net support. They are very opaque.
Wish me luck on that.
In any event, thanks for your prompt support of a great product.*

z_owner

*satisfied customer since 2006!

Sorry, but I don’t have experience with the AT&T interface. Hopefully their support people can help you turn off the filter. In the event that doesn’t work, you could try using the SpamSieve AppleScript to rescue the good messages.

Update. I am having some initial success without changing the preference in sbcglobal.net mail. I still am unable to access the preferences at the server level.
I logged on to my sbcglobal.net webmail and looked in the server side Spam folder. I manually selected those items being mis-labeled as Spam. I mark these items as not spam at the server level. After, I find that they are not getting moved to Spam at the server level and are hitting my Inbox. I may have to do this for a few days, but I think it will take care of most of my problem. This process also confirms your evaluation; the mis-marking as Spam is happening at the server level.
Thanks,
z_owner