Hello,
I’m experiencing an issue with my iOS app that uses CoreBluetooth in combination with beacon monitoring. My app is designed to wake via beacon region monitoring and then start scanning for a specific BLE peripheral (with specific service UUIDs). When the device screen is bright (i.e., the device is unlocked, or locked but the screen is active/bright), everything works perfectly—the connection is established and maintained without any issues in both: foreground and background.
However, when the device is left alone for a while and the lock-screen dims (sleeps), the app continues to run in the background and range the beacon (I can confirm this via realtime console logs), but the connection attempt fails. Here’s what I observe:
The central manager’s delegate method didConnect is called, indicating that the peripheral was connected.
Almost immediately afterward, didDisconnect is triggered with the error message:
"The specified device has disconnected from us.".
The interesting part is (I repeatedly see this error in the console, because the app repeatedly tries to connect to peripheral until a success), when I touch the lockscreen (not unlock, but just touch, which makes the screen to light up brighter), the connection is being established without any further issues!
I have the necessary background modes enabled in the app’s capabilities (e.g., bluetooth-central, location-always-mode, etc..). My expectation was that, thanks to beacon monitoring, the app would be awakened when needed, and scanning/connection would work reliably in the background regardless of whether the device is active or dimmed.
My questions are:
Why might the connection fail with this error when the device is locked/dimmed?
Is this behavior expected due to iOS power management policies even if the app remains active in the background?
Is there a way to ensure a reliable connection in such cases?
Any insights, workarounds, or suggestions would be greatly appreciated. Thank you in advance!