Hello  @camille123 ,

Welcome to our community.

Since you've already reviewed your router's security settings and everything appears to be at default or disabled, let's go through some additional troubleshooting steps:

1. Test on a different network: Connect your PC or smartphone to a different Wi-Fi network (such as a mobile hotspot) and try accessing WeTransfer. This will help determine whether the issue is with your router/SIM plan or with WeTransfer itself.

2. Check Parental Control settings: Even though Access Control is disabled, it's worth double-checking Parental Control settings, including any content filtering or website blocking that may have been set up. More info here: How to configure Parental Control on TP-Link Wireless Dual Band 4G LTE Router

3. Disable any VPN: If you're using a VPN on your device, try disabling it to see if that improves access to WeTransfer.

4. Restart the router: A simple reboot can often resolve unexpected connectivity problems.

5. Try disabling the IPv4/IPv6 firewalls temporarily: Since WeTransfer is specifically reporting a firewall issue, you can try temporarily disabling the SPI firewalls on your router (Advanced > Security > Firewall) to test if this resolves the issue. If it does, re-enable them afterward — it's recommended to keep the firewall enabled for security. Note: only do this as a diagnostic step.

6. Update your router's firmware: Make sure your router is running the latest firmware. Go here: Archer NX200(EU)_V2_1.3.0 Build 260311. Instructions are available here: How to upgrade the firmware of TP-Link 5G/4G Routers