Hi all, after two days going through forums, knowledge bases and such, I'm getting rather hopeless. Here's the challenge: Recently started a new job. Got a laptop with windows 10 and office365 all pre installed. But I'm not a windows fan, so I've installed linux mint 17.3 on the laptop. All works great. I've also installed Thunderbird because I don want to use the Outlook Web Application (OWA). syncing emails is working great. However, I also want to use the calendar feature in Thunderbird. My calendar in Thunderbird must be synced to the office365 outlook calendar so my collegues can see if I'm available for a meeting or not. So I've installed lightning and Exchange EWS provider. and there starts the problems. when I want to add a new calendar, and choose the option "on the network" I see the option to create an exchange calendar. I have to put in an URL for the location, so I've paste the following: https://outlook.office365.com/EWS/Exchange.asmx But I get an error: error code: 0x80570015 [Exception... "Component returned failure code: 0x80570015 (NS_ERROR_XPC_CI_RETURNED_FAILURE) [nsIJSCID.createInstance]" nsresult: "0x80570015 (NS_ERROR_XPC_CI_RETURNED_FAILURE)" location: "JS frame :: resource://calendar/modules/calUtils.jsm -> file:///usr/lib/thunderbird/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/calendar-js/calCalendarManager.js :: cmgr_createCalendar :: line 440" data: no] I don't know what to do next. If anyone could help me, that would be great.