I was connected to Cox Communications and gmail with no issues, everything was going fine, now cox has updated their port numbers and not getting any email at all. Also getting the warning “Password required for IMAP, Authentication failed” all the time.
What Can I do?
If they changed their port numbers then you need to update that information in your account settings.
Go to Menu > Tools > Accounts, and select the Cox account and enter the new information in the IMAP/POP3 and SMTP sections.
Hello, I have a problem sending emails after Cox Communications changed their port numbers. I have changed the Port numbers inside of eM Client to the numbers they require but now I can not send emails. I have screenshots of all the error messages. Is there a support ticket system where I can send the screenshots ? Thank you in advance.
Change your settings to
Host: smtp.cox.net
Port: 465
Security Policy: Use SSL/TLS on special port (legacy)
If that does not work, and you still want to post your screenshots, you can do that here. Just click on the camera icon when composing a reply, and you can add your pics.
Ok I had “Force Usage of SSL / TLS” selected instead of Special Port (legacy). That solved the problem. Thanks !
Happy it’s working for you now. 
Before Cox changed the port numbers everything was going smoothing.
I also have a gmail account on eM Client and it works flawlessly. Here are the settings I have and still nothing.
Hi RichB
Please change your settings to:
Host: smtp.cox.net
Port: 465
Security Policy: Use SSL/TLS on special port (legacy)
Host: imap.cox.net
Port: 993
Security Policy: Use SSL/TLS on special port (legacy)
Unless you are using different usernames and passwords for the IMAP and SMTP connections, there is no reason to select Use these credentials. Normally Use identity credentials works just fine.
I tried Legacy with no luck.
Now this is what I got… (I have the proper name and password in there)
Maybe Marc can give you his IMAP settings, as they are working for him.
Thanks for all the help guys, I have been using Thunderbird, and it works but sending out messages is like going thru an act of congress. Whereas when eM Client was working messages went out immediately even with attachments. Done for the night.
Still would like to get eM Client working again.
I dread having to install Outlook, as I have not heard anything good about it.
One thing you could try is to remove the account from eM Client, then add it again.