I received this error today and took quite some time to find the correct solution. Most articles advise resetting NVRAM and SMC but that made no difference for me.
What did make a difference is running the Apple Diagnostics tool. Not sure why, but running diagnostics must have reset something, and it got me going again. So if you have this issue with your Macbook, shut down the machine (apple icon, shut down) and then when powering back on, press and hold the "D" key.
That will start the diagnostics utility. Let it do it's thing and it will pop a report out at the end. For me, it complained that I didn't have the power connected but no problems otherwise.
When I restarted, wifi was back as if nothing bad had happened.
YMMV but it's definitely worth a try before taking it into the Apple store.
See this post on the Apple forum for more information.