Question about Slim Folio - 367749

Dear Sirs, A few days ago, a friend gave me a used iPad Air 2 with a Logitech slim folio keyboard. Unfortunately, the phenomenon has now arisen that I can use the external keyboard when writing with Word, but the Delete key no longer reacts. I have to switch to the virtual keyboard for this. I'm not sure if I've changed something - I have to mention that I don't know much about such subtleties in general. Thanks in advance LG