Archer C9 V4 - 5GHz Problem - not available due to restrictions in your region
I have a Archer C9 V4 US:
My router had both 4GHz and 5GHz bands configured and working normally, but two months ago the 5GHz wifi stopped working.
I accessed the admin to review the configuration and realized that the 5GHz option was desable to check it. In Quick Setup mode, I select the correct region and the wifi screen displays the following message: "The 5GHz network setting is not available due to restrictions in your region / country." with 5GHz checkbox disable to check it.
I did restore it from factory and configure it again and the problem not solved.
Can someone help me?