ERROR:Connection Request Failed, reason 7

[Dev]

I am using a NRF52-based platform and have BLE code based on the ble_app_hrs_c Hear rate monitor system.

Having set up for scan, I see many device (we have a lot of beacons around).

I can also see the device I wish to connect to and even read values advertised, such as RSSI.

However, when I attempt connection, the call returns with the above error.

I looked a the SDK code (13.0.0) and that error seems to be invalid parameter.

I have checked through the parameters and they are as in the example. I did modify most of the parameters one by one to no avail.

I also checked the stack init, it is identical to the example.

I have no whitelisting.

Since the scan works, BLE is obviously operating.

Is there a noob issue I am missing, although I am not a noob to BLE or BT in general.

[Dev]

I added the same discovery request initially made but after the MTU was changed (by the device) and it did indeed discover the services and chars correctly, including making it a secured connection it seems.

It then enabled notifications and read the battery level, although it said 0%, which is wrong, this is a big improvement.

I can build on this now for the other services and chars I need.

Thanks very much for this useful information Petter.