The last e-mail i received on K-9 from my oh.rr.com account was 3/30. Changes were made within their system and i can receive e-mail at their site, but cannot send or receive those e-mails at yours. I tried to match their settings on their site on your site, but it isn’t working.
If you have any suggestions, please let me know. Thanks.
Username: Your full Spectrum-provided email address
Password: Your Spectrum-provided email password
SSL: On
Protocol: IMAP
Incoming Port: 993
Outgoing Port: 587
Requires Authentication: Yes, or checked
Port 587 is the common port for StartTLS, so select this rather than SSL/TLS on the SMTP outgoing server page.
Can you test without any VPN, Antivirus or Security app enabled on your phone.
Ref: This reply to a user with similar Spectrum issues on Mozilla support here.