Hi @RAGAVENDAR SWAMINATHA SUBRAMANIAN,
Thank you for reaching out. Based on experience, one common reason these emails or attachments are being blocked is due to Outlook’s built‑in security protections. Outlook has long included features designed to block attachments or links that may pose a potential security risk. Even if a file is legitimate, certain file types, links, or shortened URLs can still be flagged automatically as a precaution to prevent malware or phishing attacks.
There are a few things you may try to reduce this behavior. If you’re in contact with the sender, you can ask them to upload the file directly to a trusted cloud location such as OneDrive or SharePoint and then share the access link instead of sending the attachment itself. Another option is to ask the sender to compress the file using a tool like WinZip or to temporarily rename the file extension before sending, as this sometimes prevents automatic blocking.
You may also want to add the sender’s domain to your Safe Senders list in Outlook, provided you’re confident the sender is legitimate. This can help Outlook trust future emails from that source.
If the issue continues despite these steps, I would recommend reporting this to your organization’s IT administrator or security team. They have visibility into your organization’s mail protection policies and can verify whether these emails are being blocked by Microsoft Defender, Exchange Online Protection, or other security rules in place.
I hope this gives you some clarity and helps point you in the right direction. If you have any additional details or updates, feel free to reply here and I’ll be glad to assist further where I can.
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