This was on android 9, but I also get the same error on my tablet, which runs android 8.1.0, and on my old phone with android 4.2.1.
I also did a test by using t.t.ExternalStorage instead of t.SDcard, but this also result in a similar error.
Using ES-fileExplorer I do notice that if I stay at folder which apear to be /storage/emulated/0, and then go up one directory then I will be at /storage/emulated which is empty
Googling this issue reveal other usersdebating this issue https://forums.androidcentral.com/samsu ... empty.html
, and it may look like google did some changes some time after android 6, that makes the directory protected in some cases.
Now as a workaround, I did test to just use /mnt/sdcard as the path instead, which does seem to work on the three devices I have tested.
BTW. I miss an Android section at this forum. You do have the APK Compiler section,but as it is labeled today, it seemes to be for compiler issues only. The newly created Remedios section is labeled more generally to cover all iOS related stuff, perhaps the APK Compiler section could be labeled a similar way?