There are several ways to get help. You use any of the methods described immediately below, or you can use the "Email developer" link on Google Play. Calibre Companion has a "Help" screen with a button to send email to us from your device.
Reporting problems or asking for help in reviews on Google Play is the most difficult for us. Our first problem is contacting you for more info; it isn't easy to find an email address for a reviewer, and might be impossible. The second problem is that other people who might have solved to problem cannot answer at all. The third problem is that we can't be sure that you even want a response and that you might consider us contacting you an invasion of privacy. We are not suggesting that people should not leave reviews, good, bad, or indifferent. Instead, we are suggesting that if you want support from us, there are better ways to go about contacting us than a review.
It could be that we will need a calibre debug log to solve the problem. You can get a debug log by running calibre in debug mode. Start calibre, then click the small down arrow next to preferences as shown in this screenshot.
Click on "Start calibre in debug mode". Let calibre restart and answer OK to the dialog that confirms that calibre is in debug mode. Attempt to connect to calibre. Get to where you are having the problem, then close calibre. You will see a debug log in a new window, probably in a text editor. An example is
Copy all the text in that window and send it to us.