Many iPhone 5, 6s/7 and iPhone 8 users are reporting that they are not able to connect to Bluetooth hands free, Bluetooth speaker, Car Bluetooth or other Bluetooth devices after they forget it from iPhone list. Sometimes the users mistakenly hit forget this device for Bluetooth hands free and cannot find device again to reconnect. The issue is very strange as once the iPhone was told to forget the device, Now the iPhone is unable to find this Bluetooth device. Resetting the iPhone and network setting does not seems to fix the issue.
How to fix iPhone/iPad not connecting to bluetooth device after forgotten :
Fix 1: Put the Bluetooth in pairing mode
If you forget the Bluetooth device it will unpair it from iPhone . It will never connect again until it is re-paired. You may think to fix the issue in iPhone or iPad, but the solution is to put Bluetooth device/speaker back into pairing mode.
You must put the device into pairing mode. You need to check the Bluetooth device manual to check how to re pair the device to iPhone. In case you don’t know it ( for Bluetooth headset devices with three buttons), Keep pressing power button and up volume bottom at the same time, immediately appeared “pair device” should come up.
Don't forget to turn on the 'personal hotspot' in 'settings'.
Fix 2:Hard Reset your iPhone :
Hard Reset your iphone and should be able to connect to my forgotten Bluetooth device again!
To Hard Reset iPhone 7 and 7 plus: hold down the power button and volume down button at the same thing until it turns off and apple logo appears.