Solved Cannot connect to spectrum (charter.net) mail server

Background. I had a roadrunner e-mail account but it was deactivated by Spectrum when a new contract for our apartment complex was implemented on 9/28.
Spectrum set up a new e-mail with a .spectrum.net e-mail address.

I deleted the old account on Outlook (latest Office 365 version) and Mailwasher Pro. I set up the new account on Outlook, with parameters published by spectrum but it doesn't connect. Same with Mailwasher Pro but after another reboot it now works. I also tried Windows Mail and it failed to connect. This is on my Win 11 Pro 22H2 system.

Now the "kicker". I dual boot with the Insider installation. It also has Outlook (office 365) and Mailwasher Pro installed. I tried Windows Mail and it auto set up successfully and I received a test e-mail successfully. But Outlook fails.

The Spectrum setup parameters:
SSL ON
IMAP
Incoming port 993
Outgoing port 587
Requires authentication: Yes or checked
Both incoming and outgoing mail servers: mobile.charter.net

Security on both systems is Defender and Malwarebytes

Edited for updates

As Mailwasher has no problems connecting, and Outlook had no problems with a POP account, but does with an IMAP would that lead to an Outlook problem, or some OS issue? There was a difference in Firewall configurations between Mailwasher and Outlook. I changed Outlook to the same as Mailwasher and nothing changed.

I have a laptop with Win 10. Tried setting up Outlook and it failed. Tried Mail and no problems setting up account (and receiving e-mails).

That leaves Outlook on any OS (Win 10, Win 11 22H2 and latest Win 11 Insider) and Mail only on my Win 11 22H2 installation.

As it appears, after much research, that there is some configuration error (corruption) in the Charter (Spectrum) setup for my account.

I can receive mail but cannot establish send on any OS/App and on my iPhone.

I'll be getting back with support today (hopefully someone competent) to get it resolved.

Contacting Spectrum was a waste of time. All he wanted to do is point fingers "not my problem". Having managed a large LAN/WAN Network and hardware help desk with multi-vendors I know all too well the "its not my problem" BS.

I did have him delete the e-mail account and have to wait 24 hours to have a new one created. If lucky it will all work.

On both POP and IMAP accounts, when one can successfully login to their mail server and is able to receive email but NOT send emails, this usually points to the the smtp outbound port.

Port 25, the standard SMTP port for moving messages between mail servers, is often blocked by ISPs and cloud providers

Port 587 is the default port for SMTP submission on the modern web. Port 587 may be blocked in your firewall. https://www.techwalla.com/articles/how-to-enable-port-587

Port 2525 is not an official SMTP port but it is still popularly used as an alternative to port 587 for SMTP submission and most ISPs and cloud hosting providers do support port 2525 for SMTP. If port 587 is blocked, port 2525 makes a good alternative.

glasskuter said:

On both POP and IMAP accounts, when one can successfully login to their mail server and is able to receive email but NOT send emails, this usually points to the the smtp outbound port.

Port 25, the standard SMTP port for moving messages between mail servers, is often blocked by ISPs and cloud providers

Port 587 is the default port for SMTP submission on the modern web. Port 587 may be blocked in your firewall. https://www.techwalla.com/articles/how-to-enable-port-587

Port 2525 is not an official SMTP port but it is still popularly used as an alternative to port 587 for SMTP submission and most ISPs and cloud hosting providers do support port 2525 for SMTP. If port 587 is blocked, port 2525 makes a good alternative.

Click to expand...

I have the corrrect port/server (verified many times). 587 is what spectrum/charter specify. I wish it was as simple as that, not in my case.

I had the identical problem trying to set it on my iPhone 12 and IOS 15.

Firewall is set to "all" for MSOutlook, Windows mail and Mailwasher Pro so not blocked.
Identical problem on Win 10 and 11.

Outlook, mail and iPhone all worked with my old POP Roadunner email.

Fixed. Deleting email account and establishing new fixed the server problem.

I ran into a similar issue recently last Fall in 2023 and found this post. I tried many things but it seems Spectrum is perhaps blocking port 25 as even setting up SMTP on my Windows 2016 server would not allow sending of mail while on spectrum, but would if I connected the same server to another ISP. Ultimately I saw a reddit post suggesting the Free service (for 1000 emails a month) smtp2go. I set that up this week and for now that will solve my use case. Just sharing hoping this helps someone else.