home made cough sweets didn't set properly

please could you let me know what went wrong - have made these before and they were slightly soft, but edible. This batch half set, but still runny Method:

1 cup sugar 1/2 cup water 1 tablespoon lemon juice 1 tablespoon honey 1/2 tsp ground ginger 1/4 tsp ground cloves simmer for 20 minutes on low heat, take off heat and allow to cool slightly, drop onto baking paper. dust with icing sugar