tbs crossfire

Hey, I have soldered my tbs nano rx to my IFlight succex-E F405, but when I push the bind button while I put the battery on, it doesn’t flash green, it does nothing. I am a beginner with this. What could I have done wrong?

Brand new fpv pilot. I thought I had done enough research on everything but clearly I'm still lacking some knowledge. I bought dji goggles, iflight nazgul5 hd V2 6s with crossfire, and a tbs tango 2. Bound everything, connected to betaflight, double checked fc inputs and they match the radio and...

There is two versions of TBS crossfire TX : Frequency Bands: 868MHz (EU, Russia) / 915MHz (USA, Asia, Australia) Many suppliers explicitly give a choice of FB on TX. So I assume it is locked and not switchable. However I don't see any reminder of frequency band on RX. When you buy a BNF drone...