Updated README

Author: sdiemer

README.md

@@ -16,7 +16,18 @@ This Moodle plugin is required for other UbiCast plugins (Atto button and Block
 Dependencies:
 -------------
 
-This plugin requires `Moodle` >= *3.0* with `mod_lti` (`external tool`) enabled and `MediaServer` >= *8.1*.
+* `Moodle` >= *3.0* with `mod_lti` (`external tool`).
+* A UbiCast MediaServer web site (version >= *8.1*). Visit https://www.ubicast.eu/en/solutions/delivery/ to ask for a trial.
+* Cookies must be allowed for the MediaServer web site (see note below).
+
+
+Important note about cookies:
+-----------------------------
+
+In order to make the LTI authentication work, MediaServer needs cookies usage.
+If your MediaServer is using a domain totally different from your Moodle domain, cookies will probably get blocked by browsers because they will be classified as third party cookies.
+To avoid MediaServer cookies to be considered as third party cookies, we recommend to use a sub domain for MediaServer using the same top domain as the Moodle site (for example, if your Moodle uses `moodle.yourdomain.com` as domain, you can use `mediaserver.yourdomain.com` as MediaServer domain).
+It is also possible to allow third party cookies usage in the browser settings.
 
 
 Installation: