Nodes list empty in Modern UI

I recently installed Knime 5.4 and some extenstions and built a simple workflow. All good. Today I installed few extra extensions and also dragged this component into the workflow: RegressionPlotter – KNIME Community Hub

After that the list of nodes in the Modern UI is empty. It seems OK with the classic UI. I tried the solution mentioned in the following Topic: the nodes load 78% and get stuck on

Knime 5.1.0 - Repository is empty in Modern UI and workflow from Knime 4 does not open in new interface - KNIME Analytics Platform - KNIME Community Forum