Hello NafaaOri,
Good day! Thank you for posting to the Microsoft Community.
This issue was posted to Service Health starting April 1, 2024, at 14:13:48 UTC.
Incident number: EX764050
User impact: Users can't download attachments from Outlook on the web.
More info: While we’re focused on remediation, users may log out and back into Outlook on the web to temporarily mitigate the impact.
Current status: We’re validating a potential fix to address what we suspect is an issue affecting a specific URL leveraged in the process of downloading attachments from Outlook on the web for some long-running sessions in the client, resulting in the impact. As we continue the process of validating our potential fix to confirm our findings, we suggest that affected users log out and log back into Outlook on the web to temporarily mitigate the impact.
Scope of impact: Your organization is affected by this event, and some users attempting to download attachments from Outlook on the web are impacted.
Users can view current information and updates on the Service health dashboard at the link here https://portal.office.com/servicestatus.
For affected customers to easily identify the information here, this thread will be closed. You may click on "I have the same question" in this thread or refer to SHD for updated information. I will also post back here once the issue is resolved on SHD.
Sincerely,
Simbarashe | Microsoft Community Moderator