Maybe you have to set the label of the item, so please try
Dimmer Led_R "Red [%d %%]" (FF_Nishit, Lights){http=">[*:GET:http://192.168.0.108:5000/red3/%2$s]"}
(removed spaces for better readability)
Maybe you have to set the label of the item, so please try
Dimmer Led_R "Red [%d %%]" (FF_Nishit, Lights){http=">[*:GET:http://192.168.0.108:5000/red3/%2$s]"}
(removed spaces for better readability)