I have Thinkpad L420 which has been rebuild recently and after rebuild we found that there is red X sign showing on network icon whereas Lan and wireless lan both are working fine. Also after switching off the wireless lan, this Red X sign disappeared.
Kindly go to Network and Sharing Centre then Change adapter settings and delete the Incoming Connection if any
Restart the system and check, if the issue persist then uninstall the wireless lan driver from device manager and
Right Click on my computer--> Manage-->Local Users and groups-->Groups--> in right panel Double Click Users - Remove all NT_AUTHORITY
After this scan for hardware changes and install the driver. Also look if there is any virtual driver in network adapter category in device manager and if find disable it.
Please try these steps and let us know the result.
Did someone help you today? Press the star on the left to thank them with a Kudo! If you find a post helpful and it answers your question, please mark it as an "Accepted Solution".! This will help the rest of the Community with similar issues identify the verified solution and benefit from it.