Occasional problem with services discovery

[Spirit]

Hello Nordic!

Sometimes we have a problem with a services discovery.
We have no custom services. Only DIS, BAS, NUS and DFU. (nRF52832 and SDK15)

This problem is currently occurring only on Motorola (E, G) and on a Huawei Nova. All three androids.
When it happens, it happens in our app, as well as in nRF Connect.




On other androids like google phones (Nexus 5, 5X), Samsung phones and iPhones the problem never come up.

Where can we search for a cause of this problem? Where to dig?
Has anyone had similar problems? How did you solve them?

[Sigurd]

Hi,

Could you try to refresh the device cache, and see if that solves the issue?

You can do this in nRFConnect like this:

[Spirit]

Sigurd, thank you for your answer.
We will try that asap it happens again.
I will report the results.

But, anyway, in the meantime, about which cache we are talking about?
And how this cache it is related with service discovery?

[Sigurd]

We are talking about the cache on the smartphone. Smartphones will typically cache the service and characteristics it discovered last time it connected to the BLE device. In that way, it doesn’t need to do the service discovery procedure each time it connects to a known device. With caching, time is saved and a significant amount of packets exchanged between the client and server is not required.