My ZigBee experiment setup is like this:
A coordinator and a single End-Device, with the end-device periodically transmitting a buffer of about 1KB. The end-device breaks down the buffer into multiples of 80 bytes. Data is sent over using AF_DataRequest without the AF_ACK_REQUEST option. Upon receiving a successful AF_DATA_CONFIRM_CMD the next 80B is sent over.
Now, the problem is that sometimes OTA transmission fails with AF_DATA_COMFIRM_CMD status as ZMacChannelAccessFailure(0xE1). Using the sniffer i can see that the 80B data never made it out of the enddevice. This problem happens at random times and sometimes doesn't happen at all. I have checked the documentation but cannot find any explanation for ZMacChannelAccessFailure.
So, what is the meaning of ZMacChannelAccessFailure and what causes this failure?