Enviar, receber e organizar e-mails no Outlook.com
Could you please confirm whether the rejection also occurs when sending a completely new email containing only a short sentence, with one recipient, no signature, links, images, or attachments? Also, approximately how many condominium notices do you normally send per day, and do you send them individually or to several recipients simultaneously?
Sender.office.com is not the appropriate tool for requesting the removal of a sending restriction on a personal Outlook.com mailbox, since you do not manage the underlying Microsoft mail-server IP addresses.