Hi,
From May the 5th the certificate for this URL seems to be expired.
https://cesiumjs.org/releases/1.17/Build/Cesium/Cesium.js
Normally it redirects to: https://cesium.com/downloads/cesiumjs/releases/1.17/Build/Cesium/Cesium.js
but now the certificate issue deny this redirection.
Do you think the certificate issue can be fixed on the old URL ?