Reconnect aftter turn off and turn on BT while connected with device

Question

Hello 
 
 *Environment 
 - LG V30 (Android 9) 
 - nRF52832, 15.3.0 SDK, S132 
 - nRF5340 ( I can't find SDK version) 
 
 I have some issue. 
 
 LG V30 Mobile can't reconnect after turn oof and turn on BT while connected with device. 
 If i wanna reconnect, I should scan again and connect to found device on scanning. 
 
 But, Samsung Galaxy Note8 (Android 9), Note 9 (Android 10) is going to reconnect. 
 
 How can I solve this problem? 
 
 Thanks.

this is demo video site. 
 https://cafe.naver.com/kindplayer/5667

Sigurd · Accepted Answer

Hi, 
 Looking at the first video, it seems like the phone is actually trying to connect to the device, but it failed to connect. 
 Does the log show any error codes? You can bring up the log If you swipe from left to right when in the device tab, or by clicking on the "3 dots button" and click "Show log".

Sigurd · Answer

From the log you uploaded we have this: 
 
 V 10:14:48.558 Connecting to DE:CF:F2:4A:CE:8C...

D 10:14:48.559 gatt = device.connectGatt(autoConnect = false, TRANSPORT_LE, preferred PHY = LE 1M)

D 10:15:18.566 [Callback] Connection state changed with status: 133 and new state: DISCONNECTED (0)

E 10:15:18.575 Error 133 (0x85): GATT ERROR

I 10:15:18.575 Disconnected

It happens in different occasions. We have observed it on: 
 1) packet collision 2) CONNECT_REQ missed by the target 3) timeout (30 or 20 seconds after connection was initiated) 4) in general, an expected packet wasn't received or an unexpected was. 
 It used to be much more common in old days, now we see it less and less with the new phones, but the low-end devices still have a lot of problems with them. Very often it is enough to repeat the last operation, for example the connection request from the phone and it should work. Maybe you could also try to change the advertising interval on the nRF5x, and see if that makes any difference.

Reconnect aftter turn off and turn on BT while connected with device

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