The error message "Air duct blocked" indicates that the dust compartment, cyclone assembly, extension rod or smart multi-brush bar may be blocked and the filter is dirty needing to be cleaned.
Please follow the video in the below link to check if there is blockage and clean the filter and cyclone assembly.
https://drive.google.com/file/d/10CA6XGk-sJHnoLi7sm9SgF2BhvJu9lHP/view?usp=sharing
Please try to use it after drying thoroughly to see whether the error exists.
If issue persist, please contact dreame support team and send a video to show the whole checking steps and the faulty result for further analysis and solution.