GATT Error 133 (0x85) Android 6+ nrf51

[Andrew]

Hi everyone,

We're using our own customized BLE service with nrf51 on the one side and Android Smartphone on the other. While connecting to the GATT I'm getting Error 133 (in onConnectionStateChange()). The frequency depends on the phone I used. For example,

• SM-G318H (Android 4.4.4) very rarely
• SM-J510FN (Android 6.0.1), SM-G950F (7.0) occasionally
• ALE-L21 (Android 6.0) almost always

All is the same way whether I use our android application or nRF Connect. After I invoke GATT connect() there is some delay (20-30s) and after that I receive Error 133 in onConnectionStateChange() in BluetoothGattCallback. Here is the screen with logs from nRF Connect screenshot.png

The main problem is that some phones are unable to connect to device's GATT. What I've tried to do:

1. Add reconnection time intervals 100-400 ms. It helped, but not as much as I want. ALE-L21 didn't get any better.
2. Force Close and Clear Data in the bluetooth adapter.
3. Add some delays in different places of the code (for example, before reading characteristic, but the problems appears earlier).

Do you have any ideas how to solve this problem at least for ALE-L21 ?

[Hung Bui]

Hi Andrew,

Please try with our unmodified example in the SDK. Also please try to turn off wifi when you test.

It seems more likely an issue on the phone side. Error 133 (0x85) is common BLE error. Happens when the phone can't connect to the device. There isn't really a solution for it. But it rarely happens on newer phones.