Our company uses a shared legacy bellsouth.net mailbox through AT&T/Yahoo, accessed by several computers and a phone. I was asked to archive more than 50,000 messages into year-based folders and began moving them in large batches from New Outlook. The client crashed during one of the moves, after which Outlook clients stopped syncing. Messages appeared to send but vanished, folder changes reverted, and nothing showed up in webmail.
I rebuilt the account in Classic Outlook using a newly generated AT&T secure mail key. It worked for about a day, including receiving mail and sending a test message. The next day, after heavy webmail activity—including moving large batches of messages out of Trash, blocking many senders and domains, and changing security settings—mail stopped syncing again.
Webmail still receives messages, but sending fails even for a plain test message with the error: "Your message cannot be sent because it resembles spam and/or contains only links." Classic Outlook is no longer receiving, outgoing messages remain stuck in the Outbox, and the account setup wizard reports that something went wrong. The account uses IMAP at imap.mail.att.net on port 993 and SMTP at smtp.mail.att.net on port 465, with SSL/TLS, full-address usernames, SMTP authentication, and an AT&T secure mail key.
Could this be an abuse, rate-limit, or reputation block caused by the bulk IMAP operations? Is the restriction likely tied to the mailbox or the office IP, and does it normally expire? Are there known limits for large IMAP moves, and is there an AT&T escalation path that can investigate or remove a mail restriction? I am not an IT technician, and the company currently has no dedicated IT support.
1 Answer
The immediate priority should be preservation rather than more cleanup. Avoid bulk moves and mass deletes, keep any remaining mail accessible through webmail, document the exact timestamps and error messages, and contact the provider through its business or legacy-mail support channels. Ask specifically for an outbound abuse block, IMAP throttling, account lock, or IP reputation issue. There may not be a published threshold for moves, and frontline support may not expose the internal reason, so an escalation request with those details is more useful than repeatedly changing Outlook settings.
Also make sure management understands that this was a systems problem, not simply an Outlook configuration issue. Without proper administrative access, you may not be able to repair or safely migrate the mailbox yourself.