Sending, receiving, and organizing email in Outlook.com
Hello RikMorskate
Welcome to the Microsoft Community.
I understand that you have not been successful in receiving certain emails and that you have made some attempts to add a safe sender and then successfully received the corresponding emails.
Try visiting outlook.com using your browser and check the current spam filter level. Adding the sender’s address to the trusted sender list can better ensure the receipt of emails. Check your various rule and filter settings. These settings may cause emails to be intercepted.
If there are no issues with your email settings and the sender has confirmed that the email was successfully sent, the email might have been intercepted during transmission. This is usually due to the email containing spam-like characteristics, such as sensitive words, links, or a large number of images. Inform the sender to try sending a plain text email or to send files and images as compressed files, which might help.
Additionally, if there are any anomalies with your IP range, it could also cause issues with sending or receiving emails. You can try sending or receiving emails from a different IP.
If an email is filtered during transit, there is actually little that individual users can do. Additionally, the transit servers come from different providers, and the filtering strategies they apply are not the same.
You can also request the customer service team to check the status of your account from outlook.com. Visit outlook.com, click Help - Help, enter your question in the description of the problem on the right, then click Search, and underneath the searched answer, select Still Need Help to enter the live chat window for consultation.
Please feel free to let me know if you have any further updates, thanks.
Best Regards,
Forry.F - MSFT | Microsoft Community Support Specialist