I have a 1st and 2nd generation Chromecast. I get the same error while only using Shaw TV. My Netflix and Prime video work fine. Very frustrating!!!
@khammond1957 The Chromecast issue is being discussed over here.
https://support.shaw.ca/t5/tv-discussions/casting-to-chromecast-error-message-tvapp-00115/td-p/41375
@khammond1957 -- the Chromecast issue is also being discussed at: https://support.shaw.ca/t5/tv-discussions/bluecurve-tv-app-not-casting/td-p/28643/
Since this is a peer-to-peer forum, not a direct path to Shaw Support, there is no authoritative "timeline" for a fix.