Trying to set up and sync with my Google Calendar. It asks if I want to add an existing or create a new account. I select existing account and type in email and password and it can't open because the account already exists. Is this a common problem?
I have installed the application and used it accordingly. I was able to link my calendars without adding or logging into my Google account because it syncs it automatically with the account attached to the device where this application was installed. If you have issues with the software, then I recommend reinstalling it or reporting this bug to the developers. You can find the contact details on its application page at Play Store.