Here are some steps to fixing a MAC address filtering problem:

1. Check Network Device Settings – Check your router to make sure it has the correct network settings, and verify the MAC address is correctly recognized.
2. Disable MAC Filtering – Disable the MAC filtering feature to see if that resolves your issue.
3. Change IP Address – Try changing the IP address of the device experiencing the problem. This can be done within the network's settings.
4. Configure Device Network Settings – Manually configure your device's network settings according to your network's parameters.
5. Check Firewall Settings – Check that your firewall is not blocking the device's MAC address from connecting.
6. Check For Outdated Drivers or Software – An out-of-date driver or software can cause the issue. Update them if necessary.