When running a task or working on a strategy, errors in the session or the syntax of conditions and formulas are signaled at the offending node.

The frontend application marks errors by drawing a red ring around the offending node and offers a brief description of the error on-screen.

When running a trading session, the session node is usually the one featuring the error notice.

When working on a strategy, errors in the syntax or logic of conditions and formulas are displayed similarly. In such a context, make sure you turn on the Formulas & Conditions layer of the corresponding session and look around within your workspace. Hover the mouse pointer over the node with a red ring and you should get a description of what is that is causing the unexpected behavior.

Notice the red ring and the error notice in yellow.

Bear in mind that when the slider is fully closed, errors occurring in a simulation will no longer show up in the design space, as shown in the below video:

The slider must be partially open showing the charting space for strategy-based errors to show on-screen