I'm using this sample code for Android from this page.
Just replaced the content of connstring from line 29 with "Hostname=<myHostname>.azureiotcentral.com;DeviceId=<myDevice>;SharedAccessKey=<myPrimaryKey>";
I'm using SAS Authentication.
The first error is when it tries to call client.open() (line 138).
It's giving me the following error each time when it's trying sending messages (line 122).
Connected to process 20170 on device '7.3_Foldable_API_30 [emulator-5554]'.
Capturing and displaying logcat messages from application. This behavior can be disabled in the "Logcat output" section of the "Debugger" settings page.
D/NetworkSecurityConfig: No Network Security Config specified, using platform default
No Network Security Config specified, using platform default
I/MultiDex: VM with version 2.1.0 has multidex support
Installing application
VM has multidex support, MultiDex support library is disabled.
D/libEGL: loaded /vendor/lib/egl/libEGL_emulation.so
D/libEGL: loaded /vendor/lib/egl/libGLESv1_CM_emulation.so
D/libEGL: loaded /vendor/lib/egl/libGLESv2_emulation.so
I/TetheringManager: registerTetheringEventCallback:com.example.kttracking
W/System.err: SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
D/HostConnection: HostConnection::get() New Host Connection established 0xf03da8e0, tid 20194
D/HostConnection: HostComposition ext ANDROID_EMU_CHECKSUM_HELPER_v1 ANDROID_EMU_native_sync_v2 ANDROID_EMU_native_sync_v3 ANDROID_EMU_native_sync_v4 ANDROID_EMU_dma_v1 ANDROID_EMU_direct_mem ANDROID_EMU_host_composition_v1 ANDROID_EMU_host_composition_v2 ANDROID_EMU_YUV_Cache ANDROID_EMU_async_unmap_buffer GL_OES_EGL_image_external_essl3 GL_OES_vertex_array_object GL_KHR_texture_compression_astc_ldr ANDROID_EMU_host_side_tracing ANDROID_EMU_async_frame_commands ANDROID_EMU_gles_max_version_3_0
W/System.err: Exception while opening IoTHub connection: java.io.IOException: Could not open the connection
I/System.out: Shutting down...
I/System.out: Message Sent: "temperature":22.84, "humidity":48.31
W/System.err: Exception while sending event: java.lang.IllegalStateException: Cannot send event from an IoT Hub client that is closed.
W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
D/EGL_emulation: eglCreateContext: 0xf03f3ee0: maj 3 min 0 rcv 3
D/EGL_emulation: eglMakeCurrent: 0xf03f3ee0: ver 3 0 (tinfo 0xf0738cf0) (first time)
I/Gralloc4: mapper 4.x is not supported
D/HostConnection: createUnique: call
HostConnection::get() New Host Connection established 0xf03f3af0, tid 20194
D/goldfish-address-space: allocate: Ask for block of size 0x100
allocate: ioctl allocate returned offset 0x3fc01c000 size 0x2000
D/HostConnection: HostComposition ext ANDROID_EMU_CHECKSUM_HELPER_v1 ANDROID_EMU_native_sync_v2 ANDROID_EMU_native_sync_v3 ANDROID_EMU_native_sync_v4 ANDROID_EMU_dma_v1 ANDROID_EMU_direct_mem ANDROID_EMU_host_composition_v1 ANDROID_EMU_host_composition_v2 ANDROID_EMU_YUV_Cache ANDROID_EMU_async_unmap_buffer GL_OES_EGL_image_external_essl3 GL_OES_vertex_array_object GL_KHR_texture_compression_astc_ldr ANDROID_EMU_host_side_tracing ANDROID_EMU_async_frame_commands ANDROID_EMU_gles_max_version_3_0
I/System.out: Message Sent: "temperature":20.74, "humidity":31.12
W/System.err: Exception while sending event: java.lang.IllegalStateException: Cannot send event from an IoT Hub client that is closed.
I/System.out: Message Sent: "temperature":26.08, "humidity":43.27
W/System.err: Exception while sending event: java.lang.IllegalStateException: Cannot send event from an IoT Hub client that is closed.
What protocol are you using? Is that a MQTT? Also please check the version of the device client are you using.
Second thing that you can do is to try on a different device and see if the issue persists. at time certain devices do exhibit issues like this.