# Invalid Certificate - All Course Videos - OS X Sierra Beta 10.12.1 **URL:** \ **Category:** 🙃 Off Topic\ **Created:** [October 13, 2016, 7:03pm UTC](https://forums.kodeco.com/t/invalid-certificate-all-course-videos-os-x-sierra-beta-10-12-1/21144 "2016-10-13T19:03:33Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![motivdev](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/motivdev/32/79544_2.png) [@motivdev](https://forums.kodeco.com/u/motivdev)\ **Post date:** [October 13, 2016, 7:03pm UTC](https://forums.kodeco.com/t/invalid-certificate-all-course-videos-os-x-sierra-beta-10-12-1/21144/1 "2016-10-13T19:03:33Z")
I can’t play any of the course videos with the latest OS X beta - 10.12.1 I’m getting the following error: > [Error] Failed to load resource: The certificate for this server is invalid. You might be connecting to a server that is pretending to be “[skyfire.vimeocdn.com](http://skyfire.vimeocdn.com)” which could put your confidential information at risk. (master.m3u8, line 0) If I bring up the web inspector and select the failed link, it says the certificate has an invalid issuer. Anyone else seeing this error? ---
**Author:** ![samdavies](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/samdavies/32/108448_2.png) [@samdavies](https://forums.kodeco.com/u/samdavies)\ **Post date:** [October 17, 2016, 10:33am UTC](https://forums.kodeco.com/t/invalid-certificate-all-course-videos-os-x-sierra-beta-10-12-1/21144/2 "2016-10-17T10:33:48Z")
Hi @motivdev Sorry you’re seeing this. I suspect this might be a change in the root certificates bundled as part of macOS in the beta of 10.12.1 you’re using. In order to determine whether it’s a problem with macOS or with our video host (vimeo) I need some more info on the certificate error. Are you able to screenshot the details of the rejected certificate? thanks sam