iOS App Bluetooth cannot connect to peripheral device

I'm trying to connect to bluetooth printers using a third party libraries. Everything works fine on iPad, iPhone, iPod touch. Now i have 3 iPad Air devices and I always got the following error message:

ERROR - sock can not connect: 2

On all other devices, the connection works fine. Any idea, what I can do?

Same problem:


  • What version of iOS is on your iPads? There seem to be some external accessory connection issues in iOS 9.3.1. They should be fixed in 9.3.2. I've tested the beta and it seems to be working as expected again.