Scott Leturno

Trouble for some Comcast Users of Canvas

Discussion created by Scott Leturno on Nov 6, 2017
Latest reply on Nov 29, 2017 by Lisa Dyrda

Please check with your User Support/ Helpdesk staff to see if any of your users are suffering from this issue that may go undocumented as home PC or browser issues. This issue appears to be a Comcast/Xfinity customer issue involving Comcast's DNS.

We had multiple users over a period of days report receiving a specific error when attempting to get into Canvas. The error was that the connection to was not secure and that there was an issue with the certificate.




We have a vanity URL and we authenticate through single sign on. The problem would occur if the users were already authenticated or still needed to authenticate.


After several days of troubleshooting with no resolution we were told this likely was an issue with Comcast, the ISP. 


We contacted other Colleges in our area since our students may share the same Comcast internet service providers and we were immediately told that not only had they suffered the same issue but that another University in the area suffered with this issue for a month before they finally had it resolved with Comcast. I'd like to thank Joliet Junior College for assisting us with this valuable and hard earned information, they and another local University were instrumental in bringing this information to you. Without their information we would still be asking Canvas for support and asking our users to reset their browser cache with no resolution.

Our trouble is ongoing. and we hope to have a solution from Comcast soon. I'd hate for you and your users to suffer through a week or month of being asked to clear browser cache and flushing DNS cache only to find out you have to contact Comcast and still wait additional days for a resolution. Our Comcast ticket was opened on Friday and is still not resolved.  Here are the relevant case numbers:

Canvas Case: 02573797

Comcast Case numbers: 

First one: CR742676296

Second one: CR743243533

And Comcast DNS Support – the ticket # is #7110  << from Joliet Junior College who gratefully shared their history with this same issue.

When contacting Comcast it appears to help to describe that you are reporting an issue of their customers getting to Canvas LMS a Learning Management System site. That you were informed that other colleges and universities  had similar issues with Comcast DNS caching old information/addresses and that Comcast was able to clear this issue from it's back end servers.

You will want to provide Comcast with the web addresses particular to your institution, your non-vanity address and the address if your trouble is as described above:


and your vanity address (ours is


We hope this resolves your issue but our own issue is on going. If anyone has had a positive outcome on this same issue with Comcast or another ISP please share your advice with the community. We all would appreciate this.


My hope by sharing this information is that your users will no longer have to suffer thinking it's their PC and browser and that as a community we can get Comcast to correct this issue for everyone. 


Scott Leturno

LMS Administrator 

Moraine Valley Community College


Edited 11/07/2017 to Acknowledge Joliet Junior College for their experience shared on this issue. I'll only share the name of the University with their permission but both of the schools were key in identifying how we needed to address this with Comcast.