cannot automatically add an AT&T e-mail account

the account was working but only downloading e-mail. I was never able to upload (send) e-mails. I checked that my username and my passwords for that account are OK by Loggin In to a Webmail/mail browser. So I completely deleted the account and followed AT&T instructions which say to add a new account using the "Other account" type of e-mail. Eventually a message from Mail tell me that: "Unable to verify account name or password." I just made sure, again, that I was able to Log In to the mail account using a Web Browser. I would very much appreciate any help in solving this problem. I am running MacOS 14.6.1