I have one phone and one pad with android system, I tried lots of different browser to try to use chess mentor / tactics trainer / online chess, but all of them could not make the move - I could choose the piece to be moved, but I could not drop it to anywhere.

do you have the same issue ? if no, can you tell me which brower you use ?

thanks

Don't "drag" the piece, select the square the piece is on , then tap where it will be going to.

yes，I do but fail

when I select the piece, it is  “high-lighted”，but when I tag the target square, nothing happened.

the ipad and iphone have no this issue, but all android devices I tried is fail.

I tried again on the Dell's new 10 inch pad on this Sunday and fail again - I use its browser pre-installed.

Ahhh, there's your problem. Don't use the browser, go and download the chess.com Android app.