General Connection Error on any wireless device connection"Send to device" (Android)

[Cris B]

This is with a newly set up Android device & clean install of Calibre Companion. The wireless device connection starts up OK. Then any time I try to send a book with 'send to device', the send starts (progress dialogue starts on the device, and 'jobs' in Calibre shows the send has started). Then it stalls, and ultimately stops with a dialog on the device saying "General connection error. There was an unrecognised error during the connection process. Please try again".

On the PC/calibre end, the log has;

calibre, version 4.12.0
ERROR: Error: Error communicating with device

timed out

Traceback (most recent call last):
  File "site-packages/calibre/gui2/device.py", line 90, in run
  File "site-packages/calibre/gui2/device.py", line 513, in _books
  File "site-packages/calibre/devices/smart_device_app/driver.py", line 50, in _synchronizer
  File "site-packages/calibre/devices/smart_device_app/driver.py", line 1379, in books
  File "site-packages/calibre/devices/smart_device_app/driver.py", line 50, in _synchronizer
  File "site-packages/calibre/devices/smart_device_app/driver.py", line 1581, in prepare_addable_books
  File "site-packages/calibre/devices/smart_device_app/driver.py", line 50, in _synchronizer
  File "site-packages/calibre/devices/smart_device_app/driver.py", line 1569, in get_file
  File "site-packages/calibre/devices/smart_device_app/driver.py", line 563, in _read_binary_from_net
timeout: timed out

I don't have any other network problems on the device or PC. I initially thought it might be Android's battery optimisation kicking in, but I've excluded CC from that in android settings with no joy.


Calibre version: 4.12.0 on Ubuntu (downloaded & installed directly from the main calibre site)
Calibre Companion version: 5.4.3.3 (391) on Android 10