If you are having issues with Google Chrome suddenly not displaying layers in your web maps/apps that are published from your own ArcGIS server. If the issue began sometime after the end of October then there is a good chance you have a SSL certificate from a certificate authority owned by the parent company Symantec which if certified before December 2017 will no longer be accepted by Chrome.
As simple as the fix was it took me a while to figure this out being that I'm not truly an IT guy and it slowly came on my radar as clients began updating their Chrome browsers. I thought I had sudden issues with how my Web Adaptor or IIS settings were configured. Multiple calls with tech support didn't yield any results either.
Update your Symantec issued certificate and everything will work as normal.
Here is the article regarding the issue posted by Google: