People you get the certificate error because the redirect to install the player is a redirect to HTTP and some computers are only setup to allow sites with HTTPS. Your QA department, your managers and your support do not understand the difference between HTTP and HTTPS. If the install is not through HTTPS its not allowed. How can you have an online application and no one can figure out this issue? Your computer system is setup to only allow HTTPS which is SSL, secure. HTTP is not secure. It is clear from looking at the error in the address bar what the issue is when it redirects it's redirecting to HTTP and again some systems don't allow this so until this changes it will not work: