Skype for Business Meeting Failed: Content was blocked because it was not signed by a valid security certificate
In either Internet Explorer or other browsers you might see this issue finally popping when you try joining a Skype for Business Server Meeting if the Meeting is hosted on Premise, This issue also pop's up with Lync Meeting, not only with Skype for Business Meetings. Error: Content was blocked because it was not signed by a valid security certificate After investigation, I saw this was most likely related to changes in Skype for Business Client Update from Januar 2016: https://support.microsoft.com/en-us/kb/3114502 It implements a new and proper described certificate validation procedure for all SIMPLE URL's. ( Note: This issue can't be replicated each time, therefore you have to consider this as "possible issue" ) As I described earlier in my blog: http://lyncuc.blogspot.de/2015/10/wildcard-certificate-support-in-skype.html It is absolute curial following the infrastructure recommendations from Microsoft, regardless if ...