Hi @RajeshNalla,

This usually appears in Constellation when the environment is mixing two different rendering backends (Traditional UI vs. Constellation) at the same time for a case type.

Both parent and child must use the same UI backend. If one is Constellation and the other is UI-Kit/Traditional, you’ll see this error.

Regards,

Mohd Qizer Uddin

@RajeshNalla This error usually means your app is loading two UI runtimes at once, like Constellation and Theme Cosmos/UI-Kit, so the authoring tool refuses to open. Pick one runtime and keep it consistent. In the Application rule, remove Theme Cosmos or UI-Kit build-on layers and keep only the Constellation stack, and set the portal to a Constellation portal. Do not mix a Cosmos parent case with a Constellation child case. Close any other tabs using a Cosmos portal, log out, clear cache, and try again in a fresh private window. In App Studio, check Channels and make sure there is only one Constellation service URL configured. If you recently upgraded to 24.x, re-save the Web channel, resync static content on the nodes, and clear rule/data caches. After that, create views from App Studio in the child case and it should work. If it still fails, trace for duplicate constellation engine loads or custom scripts that inject UI files and remove them.