Note that there is a similar library for B4i.
There is almost nothing to configure before a connection is made. So if it doesn't work then there isn't much that you can do.
I have spent hours today reading through various posts here, and on the wider www, about this issue as I too have the problem many describe.
I have an ESP32 running some small Micropython code that sends a simple 2 values from a transducer to a BLE device.
The BLE2 example app scans, finds the device, but won't Connect to it. After a timeout the Debug reports 'Disconnected'.
Serial terminal on the phone connects without issue, as does nRF Connect. As soon as the phone connects using either of these two apps I can see the ESP32 sending the 2 values......
I think the issue is in the manager.Connect2(device.Mac, False) line in the private Sub scanTimeout_Tick.
The Log entry is written on the previous line, but nothing occurs from this line onwards........
Its out of my depth but I will have a look at Github (I think I read somewhere the BLE library was open source on there) as I am curious what manager.Connect2 does....
Would there be any other pointers on what I could try to resolve this issue please ?