Miscellaneous topics that do not fit into specific categories.
Sorry to hear that some of your legitimate emails are being sent to the Bulk folder. Since this started after adding your new ATT.NET account, the Bulk folder is most likely the Spam folder from the AT&T/Yahoo mail server being synchronized with Outlook through IMAP. With AT&T accounts, the server's Spam folder can appear as Bulk in Outlook.
I recommend signing directly into your AT&T Mail account in a web browser first and checking whether the same messages appear in the Spam folder there.
If they do, select the legitimate messages and choose Not spam. According to AT&T, this moves the message back to the Inbox and future messages from that sender should also be delivered to the Inbox.