Why file attachments keep failing on my Copilot?

Dear Adeniji

Thanks for reaching out! Welcome to Microsoft Q&A. I'm Haien from Microsoft Q&A. 

I understand you're experiencing two related issues with Copilot: file attachments are failing to upload, and new chat sessions are not generating responses. The issues you've described can be caused by a few different things, particularly with a personal account. It's often related to a combination of service-side issues, local network settings, or browser-related problems.

To help me narrow down the cause and provide the best solution, could you please clarify where you are using Copilot? Is it:

• In a web browser (like Microsoft Edge)?
• The standalone Copilot app for Windows?
• Copilot integrated into the Windows taskbar?
• The exact error message when file uploads fail (e.g., “File size exceeds maximum limit” or “Unsupported file type”)?
• The file types you’re trying to upload (e.g., PDF, Word, JPEG)?
• Does the chat response issue occur with all prompts or only when attachments are involved?
• Have you recently updated Windows or Copilot, or changed networks/VPN settings?

Here's how we can try to get you back on track and please keep me updated with anything new that you were try to each option:

• Open Microsoft Store > search for Copilot > Update to the latest version.
• Ensure files are under 50 MB and in JPEG/PNG format, as personal accounts may not support PDFs or Word documents. Use an image converter (e.g., Photos app) to change file formats if needed.
• Switch networks or disable VPNs to ensure stable connectivity > Go to Settings > Network & internet > Advanced network settings > Windows Firewall > allow Microsoft Store apps.
• Press the Windows key + R, type ms-settings:troubleshoot, and press Enter > In the Troubleshoot > Other troubleshooters > Find Copilot > click Run > Follow the on-screen instructions.

For additional information about similar situation, please visit this article: File upload in Microsoft Copilot

To assist others who might have similar questions and to help us improve our support system, we kindly encourage you to "Accept the answer" if it successfully addressed your concern. Accepting an answer lets other users know that this solution worked for you, and it also helps us track the effectiveness of our support efforts.

We appreciate your patience and look forward to resolving this quickly for you.

Warm regards