PUMPKIN CAR STEREO SUPPORT CENTER

I just purchased the Pumpkin ae0273b-08a. The unit works great. However, when I plug my phone into the head unit via USB my phone says that the phone is charging slowly and also says that the connected device cannot access the files. My phone is a Samsung Galaxy S8. I don't have these issues when hooking it to a Kenwood unit in my other vehicle. I have tried other USB cords and it still gives the same issues. My two questions are

1)How many amps does the USB supply?

2)Is there a known issue with accessing files on Samsung devices?

Hi,
1.the whole current of the USB supply is 1 A .
2. as far as i know,all android system car stereo does't support access the files through phone.And this unit also doesn't support .
Regards