Duly moved. Could you send me the exact text of the error message? Where exactly is the file located in your device's file system, and how are you accessing it (recent documents history or file browser or something else? if file browser, is it in recents or internal storage or downloads or another folder?)
Also, check the system Settings app for Pleco's permissions - is Pleco's access to external storage disabled?
Also, check the system Settings app for Pleco's permissions - is Pleco's access to external storage disabled?