I bought a pair of 30Ks in November ov 2017 - my friend has since left town but I was able to connect mine with other Sena owners - until lately.
Six months back, one friend bought a Cycle Gear Bilt helmet with built in BlueTooth, which is OEM'ed by Sena. He and I were able to pair the two and that was fine - until the last couple of months.
Another pair of pals bought 10cs, and there too I was able to pair with them - initially.
But lately, attempting to connect fails - even holding the button to go into to pairing mode does not find the other units. For the past month or so, I discovered that the 30K iOS app on my iPhone would link to my 30K, and then I could see both 10c's or the Bilt helmet as possible connections and that would work. Now, however, the iOS app itself seems to refuse to connect to the iPhone! It stupidly mentions I should connect the 30K to the iPhone while the iPhone shows it as already connected. And, by the bye, I can take calls and listen to the iPhone music - so obviously on one level the Sena "knows" it's connected. But the app has gone brain dead.
I did discover that if I shut down the iPhone altogether and restarted it, then the app would indeed find the Sena 30K (I turn the 30K on before launching the app). But today, while that did work in the morning (with the Bilt helmet), at lunch I powered off the helmet (to save power) and also made a video message (using Marco Polo) - then, when I returned to the bike the app refused to "see" the 30K, even after having restarted the phone and the 30K half a dozen times. Literally.
To say I am getting quite fed up with Sena's slide down the reliability scale would be an understatement. I am hoping someone has a suggestion short of waving a chicken bone to the east when starting up the app - because this is ridiculous.