Dear Eri Virden
Welcome to Microsoft Community.
According to your description, your Microsoft mailbox is not able to receive emails sent by some specific senders, while the other party clearly indicates that the email was sent successfully is it?
For this issue, there are many reasons that can lead to this problem, I suggest you can try the following process in the web version of Outlook through your browser to confirm if you can solve this problem:
- Use the search function to check emails:
You are in the web version of Outlook, click on the search function on the top to find the keywords of the emails that you can't receive to make sure if the emails are in other folders.
- Check the rules:
In the web version of Outlook, you can click the gear settings in the upper right corner - Mail - Rules to check whether there are some rules set such as Forwarding that will cause you can not see and receive emails, or you can suspend all the rules to confirm whether you can find the emails or not.
In the meantime, I would also recommend that you contact Microsoft support and have someone help you check your Outlook by doing the following:
- Click the link.–Contact - Microsoft Support
- In the box under “We're here to help,” enter Outlook, click Get Directions, and then click Contact Customer Service. (You must be logged into your Microsoft account. If not, follow step )
- In this section, you need to sign in to your personal Microsoft account.
Note: You can only sign in with your personal MSA, when you sign in with your company account, it will not display correctly. If you are unable to connect to this account, you can use another account or create a new account to manage it.
- Under “Products and Services”, select “Other Products”, select “Outlook”, and then click Confirm.
- You can select “Chat with a Support Specialist in a Web Browser” and go to the chat window.
Note: Please contact us during local business hours on weekdays, CHAT is not available 24 hours a day.
Feel free to text back if you need further help.
Best wishes
Chris.S-MSFT | Microsoft Community Support Specialist