Hot reloading doesn't work and client not available.

[igorcukovicasana]

Summary

My sandbox got upgraded to API 66.0. Local Dev either can't connect to client, or when it does doesn't hot reload anything.

Steps To Reproduce:

lightning-dev 5.1.4 (prerelease) and can't connect to client:

sf plugins install @salesforce/plugin-lightning-dev@prerelease
sf lightning generate component --name localDevTest --type lwc --output-dir force-app/main/default/lwc
sf lightning dev component --name localDevTest

Expected Result

Work properly and hot reload

Actual Result

Hot reloading doesn't work

Additional Information

Screenshots:

Logs:

be1a616……0000009OXlKAM:23228 ComponentProfiler: Component-level profiling has not been enabled.
(anonymous)	@	be1a616……0000009OXlKAM:23228
ad64725……0000009OXlKAM:11749 🔵 PREVIEW MODE: previewApplication in normal mode!
ad64725……0000009OXlKAM:11785 Client not available. Running in fallback mode.
loadComponentData	@	ad64725……0000009OXlKAM:11785

System Information

SF CLI:

{
  "architecture": "darwin-arm64",
  "cliVersion": "@salesforce/cli/2.123.1",
  "nodeVersion": "node-v22.22.0"
}

OS:
macOS 26.2 (25C56)