Last 3 years intermittently getting AUP#CXSNDR error on outgoing e-mails - now constant.

Occasionally I would get this error, but it would pretty much only pop up when trying to save a copy of the e-mail in the Sent folder. At first I figured it was just a weird permissions issue, or maybe even possibly when sending to specific servers and there was some weird glitches going on between the different servers, but now it's a constant thing. I'm even getting this when trying to send e-mails to my father and grandfather, who are both on the cox.net domain - personal accounts that were given out when Cox didn't determine that having to give e-mail addresses to their customers was too "burdensome" or "costly". In looking at the codes on your page with them https://www.cox.com/residential/support/email-error-codes.html I don't see one that has both AUP & #CXSNDR, but from my powers of reading and deduction it seems it's a mishmash of:

• AUP - which is Email sending blocked due to suspicious account activity on primary Cox account. To secure your account, please reset all Cox account passwords at cox.com/password. Contact Cox at cox.com/chat to remove block and reference error code AUP#CXMJ.
  • The fix: Reset your password at www.cox.com/password or visit www.cox.com to sign in to your primary Cox account and go to the My Profile page. Then, contact Cox at www.cox.com/chat to remove the block referenced by error code AUP#CXMJ.
• CXSNDR - There was a problem with the sender's domain.
  • The fix: Your email failed authentication checks against your sending domain's SPF, DomainKeys, or DKIM policy.

So I'm not sure what to do here. When this initial problem came up about 3 years ago, I e-mailed Cox tech support, had a little back & forth with them (they seemed utterly confused), then I quit getting responses from them regarding this, even when I initiate a new support e-mail. I'm guessing that along with free e-mail addresses to your customers, you've determined that trained tech support is too "costly" and "burdensome" as well. Or who the hell knows, maybe just having tech support at all is too "costly" and "burdensome".

Who the hell do I talk to to get this fixed? Since I'm forced to be reduced to guessing what's going on here since it would appear that Cox's "key" for the different codes is obviously woefully incomplete, I'm guessing that my account has been flagged for "sending spam" (AUP), which then causes the secondary error (CXSNDR); which is simply baffling as the only things I really send out from this e-mail address are historical e-mails to my father, grandfather and a few others as well as sending links about news or other things of that nature. The only other stuff I get is the few newsletters I subscribe to and then of course the "confirmation" e-mails when I need to start a new account somewhere.

Can someone (presumably in tech support - preferably even someone that's trained/knowledgeable) help me figure out what the hell is going on here and help me rectify it? I realize that since Cox has determined that customers having Cox.net e-mail addresses is too burdensome and costly, it's "better" for the company to drive off everyone still using those e-mail addresses so they can save money (while driving the price for services up - naturally), but I'm not about to change an e-mail address I've had for two and a half decades. Or is competent tech support something you have to pay extra for these days with your "Complete Care" package? You've already made it elusive as hell to find an e-mail address to open up a new dialog with tech support, so it honestly wouldn't surprise me.

This happens with Apple Mail (iOS & MacOS), Thunderbird (on both Linux & MacOS), Cox's webmail in an Internet browser (tried on 4 different browsers in various states of configuration), This needs to be fixed, balls in your court Cox.

Also since I'm dropping valid complaints about the erosion of service and support from Cox, there's also the giant problem with my inability to send an e-mail when connected to my VPN. The last administrations acts against Net Neutrality should have sufficiently scared the *** out of anyone who valued their privacy (hence the drastic uptick of VPN providers in the last 5 years), but it would appear that Cox is always one step ahead when it comes to ruining any semblance of privacy one might have enjoyed with them blocking connections to VPN providers should one need to send an e-mail. Again - this is something I've brought to the attention of tech support multiple times and they've simply sat there in silence with a presumably quizzical look on their face. They had no god damned idea what a VPN was. Whether that's due to insufficient training on Cox's end or simply a "business tactic" to get people to pony up EXTRA for basic tech support I'm not sure; I wouldn't be surprised by either frankly, but I'd put my money on the latter.

These aren't unreasonable requests. Just so we're clear, I need to:

• Be able to send email
• Be able to send email when connected to my VPN.

That simple guys. It's really that simple.