ContributionsMost RecentMost LikesSolutionsRe: VPN I have this problem as well. VPN on, can't send. VPN off, sends just fine. I had an issue with using COX email at my work early in 2020, and best I could find out, was that COX requires a "reverse DNS"lookup from the server that is sending the mail, and our IT folks had turned off that function with our servers. After much complaining, the IT folks at work eventually got around to make that happen again, and then mail started sending once more. Perhaps when on VPN (like at home), this Reverse DNS doesn't happen? Re: Cox Disables SSL and Now iPhone Users cannot use Mail app It's not just iPhones. I have a Mac computer at work and home. I can send and receive just fine from home, but at work I can not log on to the COX SMTP server. Same version of Mac Mail with all the same settings on both home and work machines. Called COX CS and tried changing passwords, re-entering all the mail setting etc. to no avail. The reason that shows up in my Mail Log is: READ May 01 12:30:16.903 [kCFStreamSocketSecurityLevelNone] -- host:smtp.cox.net -- port:587 -- socket:0x6000006a11a0 -- thread:0x608001264900 554 cxr-obgw-5003a.stratus.cloudmark.com cmsmtp 140.198.32.9 blocked. Refer to Error Codes section at www.cox.com/.../email-error-codes.html for more information. AUP#CXDNS I've gone to many sites (including spamhaus), and my IP address is not listed as a BLOCKED IP address anywhere? This started happening April 24...coincidentally(?) with COX's change to mail security protocols. Re: Can't send outgoing email I have same problem. I can send and receive just fine from home, but at work I can not log on to the COX SMTP server. Same version of Mac Mail with all the same settings on both home and work machines. The reason that shows up in my Mail Log is: READ May 01 12:30:16.903 [kCFStreamSocketSecurityLevelNone] -- host:smtp.cox.net -- port:587 -- socket:0x6000006a11a0 -- thread:0x608001264900 554 cxr-obgw-5003a.stratus.cloudmark.com cmsmtp 140.198.32.9 blocked. Refer to Error Codes section at www.cox.com/.../email-error-codes.html for more information. AUP#CXDNS I've gone to many sites (including spamhaus), and my IP address is not listed as a BLOCKED IP address anywhere? This started happening April 24...coincidentally(?) with COX's change to mail security protocols. Re: Can't send email Same here with MacMail. Blocked IP is the error I see in my Mail Log? I can't get anyone at COX to give me an answer...Hell, I can't even get anyone at COX to respond. I can send and receive from home using the same version of Mac Mail with all the same settings. At work, I can't connect to SMTP. Blocked IP? I have been using a cox email address for nearly 30 years. I am a Mac user using MacMail v. 11.5 (3445.9.1) on both my Mac at home and my Mac at work. I can send and receive mail as usual on my home machine, and I could last week at work until around Thursday, when all of a sudden I can notsendany mail from my machine from my work locality? All of the mail settings are identical both here and on the home machine? I can connect to "imap.cox.net" and thereby receive mail, but I can not connect to the "smtp.cox.net" outgoing server? I contacted Cox CS on Friday and we tried sending from Cox webmail - no problem. We tried changing passwords, that didn't solve it. I was being transferred to a higher level of help, and someone answered the line and then hung up (disconnected). I was tired of being on the phone for so long and did not call back. I checked my Mail log file and in there I see: INITIATING CONNECTION May 01 12:30:14.669 host:smtp.cox.net -- port:587 -- socket:0x0 -- thread:0x608001264900 CONNECTED May 01 12:30:14.781 [kCFStreamSocketSecurityLevelNone] -- host:smtp.cox.net -- port:587 -- socket:0x6000006a11a0 -- thread:0x608001264900 READ May 01 12:30:16.903 [kCFStreamSocketSecurityLevelNone] -- host:smtp.cox.net -- port:587 -- socket:0x6000006a11a0 -- thread:0x608001264900 554 cxr-obgw-5003a.stratus.cloudmark.com cmsmtp 140.198.32.9 blocked. Refer to Error Codes section at www.cox.com/.../email-error-codes.html for more information. AUP#CXDNS WROTE May 01 12:30:16.913 [kCFStreamSocketSecurityLevelNone] -- host:smtp.cox.net -- port:587 -- socket:0x6000006a11a0 -- thread:0x608001264900 EHLO (location removed) READ May 01 12:30:16.976 [kCFStreamSocketSecurityLevelNone] -- host:smtp.cox.net -- port:587 -- socket:0x6000006a11a0 -- thread:0x608001264900 503 not available I called Cox CS again today and went through the same machinations as Friday (without changing passwords again). This time though I was told I have to buy their $10/month service if I want a higher level of help...really??That was almost enough to make me just cancel all my Cox services...but...I thought I'd give this forum a try. Anybody have any insights as to why after nearly 30 years, my IP would be blocked? And only from my work location? I don't do any mass mailings. COX says check with Apple, Apple says check with COX. Round and round I go , in the meantime, I can not log on to COX's SMTP server, so I can't send mail!!