Sync with Marvin and Calibre Broken

I have the latest iOS (10), marvin 3 and calibre download but calibre refuses to work with marvin. I have followed all the instructions on syncing but every time I try to use the iOS reader plugin, it uninstalls itself and won't allow me to make a proper sync on my iphone. Here is what it says when I attempt it:

calibre, version 2.71.0
ERROR: Install Plugin Failed: A problem occurred while installing this plugin. This plugin will now be uninstalled. Please post the error message in details below into the forum thread for this plugin and restart Calibre.

Traceback (most recent call last):
File "site-packages\calibre\gui2\dialogs\plugin_updater.py", line 715, in _install_clicked
File "site-packages\calibre\customize\ui.py", line 421, in add_plugin
File "site-packages\calibre\customize\ui.py", line 588, in initialize_plugin
InvalidPlugin: Initialization of plugin Traceback (most recent call last):
File "site-packages\calibre\customize\ui.py", line 582, in initialize_plugin
File "calibre_plugins.ios_reader_apps.__init__", line 916, in initialize
File "calibre_plugins.ios_reader_apps.__init__", line 1245, in _get_connected_device_info
InitialConnectionError: Unable to connect to iDevice
failed with traceback:
Traceback (most recent call last):
File "site-packages\calibre\customize\ui.py", line 582, in initialize_plugin
File "calibre_plugins.ios_reader_apps.__init__", line 916, in initialize
File "calibre_plugins.ios_reader_apps.__init__", line 1245, in _get_connected_device_info
InitialConnectionError: Unable to connect to iDevice

Is there anything at all I can do to make a proper sync using my iphone or potential workarounds? I just have the iphone for reading so I'm very frustrated at the idea of having to redownload my books onto marvin everytime I update something on calibre. I would appreciate any help.

Thanks.