htc one e8 marshmallow 6.0.1, could not use sd card as internal memory

[AC Question]

i updated my htc one e8 to marshmallow 6.0.1 through OTA. When i'm trying to format it as internal , the pop up shows that "this sd card is too slow to be used as internal storage. Try using an UHS Speed Class 3 sd card".
i'm using samsung evo+ 32gb class10 sd card. its a brand new sd card which i bought after updating to marshmallow.