Wysyłanie, odbieranie i organizowanie wiadomości e-mail w Outlook.com
Sorry to hear that you’re having trouble with this situation. Could you please confirm whether the senders receive a non-delivery notification when they try to send emails to your address? If they do, please ask them to share a screenshot of it, as it may contain important information about the cause of the issue. Also, I see this is marked as Outlook.com, but are you using Outlook on the web, or are you using an app?