Hi there! I see you’re running into an issue where Manus rejects your requests or file uploads and prompts you to check your connection. Let's get to the bottom of this together.

First, just to clarify:
- Are you connected to the internet when this happens?
- Is your network connection stable? (e.g., try browsing other sites to confirm)
- Do you see this message every time you try to interact with Manus, or only intermittently?
- Have you tried this on a different network or device?

Assuming your internet is generally working, here are some steps we can try:

1. Check Manus Session Length or Context Size:
Sometimes Manus rejects inputs if the conversation or upload context is too large or complex—this can happen if there are many previous messages or large files. If your requests are long or you’ve been continuously interacting for a while, try starting a new session/task in Manus and attempt the upload/request again.

2. Network Troubleshooting:
- Restart your router and device (Windows machine) to refresh connections.
- Temporarily disable any VPNs, proxies, or firewalls which might block Manus from connecting to its servers.
- Verify your firewall allows the Manus app or web browser to communicate over the internet.

3. Browser & Cache:
Since you're using a WebKit browser on Windows 10, try clearing your browser cache and cookies. Sometimes, stale cached data causes connection issues.

4. File Size or Format Considerations:
If you're uploading a file, ensure it's within Manus’ acceptable size limits and supported formats. Large files or unusual file types may be rejected.

5. Update or Re-login:
If you are using an app or web interface for Manus, try logging out and back in. If there’s any update pending for Manus or your browser, install that as well.

If after checking all these you still get the "check connection" rejection: There might be an ongoing Manus server-side issue or a more specific network restriction affecting your setup.

Would you mind confirming:
- Have you tried sending a simple request (like a short message) or only file uploads?
- Has this started recently or has it happened since you first began using Manus?

Depending on your answers, I can guide you to more tailored steps or check if there’s a known service outage.

Let me know, and we’ll get this sorted! Are you able to share any error details or screenshots?