We are also experiencing this error now in two different ArcGIS StoryMap projects. When adding a new map to the Sidecar slider, it won’t open the map selection overview, but closes immediately again with no error.
The problem seems to occur very randomly. Sometimes when exceeding 5 slides or sometimes when we exceed more than 4 sidecars.
We have never experienced this problem before and it seems to have occurred after the previous update.
Christian Pedersen
GIS developer at Geological Survey of Denmark and Greenland (GEUS)
Christian Brogaard Pedersen