Using classic Outlook for Windows in business environments
That looks like a spam filter blocked it content rejected would mean the server's filter didn't like something in the message. The TT992 error code indicates that Microsoft servers are either sending too much spam to talktalk users or the messages are not authenticated.
Based on some older threads in the talktalk forums at https://community.talktalk.co.uk/t5/Email/bd-p/myemail, it seems like this issue comes and goes.
-- Diane