Can't Send Email on Charter POP Account on M1 MacBook Pro
All of a sudden a few weeks ago I am unable to send email with my Charter POP account on my M1 MacBook Pro, yet it works fine on my iPhone 13 Mini. It receives email just fine on the MacBook Pro. When I try sending, it comes back with "Cannot send message using the server smtp.charter.net", "The sender address *****@charter.net was rejected by the server smtp.charter.net". I've made no changes to the settings. I've contacted Charter (Spectrum) several times, first being told they were working on an issue that effects home computers, then another time I was told to switch from POP to IMAP that they don't use POP anymore...which is not true. This is very frustrating.
[Re-Titled by Moderator]
MacBook Pro (M1, 2020)