It is always a good idea to start with a clean Bluetooth configuration. Make sure that you remove other paired devices unless they are necessary. To do this follow the unpair devices for a clean configuration procedure.
The procedure can be separated into 3 steps:
- Step 2 - Pair the e355 with a mobile device
- Remove configuration and reboard
- Step 3 - Start a transaction
The POS app and the e355 should both use the same serial communication protocol version. At the moment this is version 2. If the protocol version differs between the POS and the e355, communication will fail. Pairing will succeed but boarding and starting a transaction will not and the app will be stuck in the initialization phase.