VEX IQ Robot will not connect wirelessly to controller

Despite updating all firmware and following the instructions carefully, 2 of our 3 VEX IQ robots will not connect wirelessly to their controllers. Any suggestions?

Usually, this is caused by the radio modules not being pushed in all the way. There is a really nice writeup about this on the Kiwibots site to help you check:

https://kiwibots.co.nz/kiwiblog/entry/vex-iq-radio-issues-not-working

I second the radios not being pushed in all the way. If done right, it sounds like they are breaking, and the VEX logo cannot be seen on the radios.

My team had this problem. I followed all suggestions mentioned here, but nothing worked.
Later in the settings i noticed that the ‘Radio data’ setting was OFF
I turned it on, recalibrated the controller and the issue was resolved.