ERR_FORECAST_ERROR on Salesforce: Forecast calculation error. Root cause: A Salesforce Forecasting operation failed. This can occur when the forecast hierarchy is misconfigured, when a user being included in a forecast rollup has been deactivated, or when the forecast period being updated is outside the allowed adjustment window. Step 1: Check formula. Review forecast formula Step 2: Verify data. Check required fields Step 3: Test calculation. Manual calculation Step 4: Refresh forecast. Recalculate forecast