That is checkmate. You are simply using a bad tool.

For simple mate in one exercises I recommend my own website.For example, this link https://www.apronus.com/chess/puzzles/mate-in-1/?2vs1 has mate in 1 puzzles where the stronger side has two chessmen against a lone king. The good points about my system are:

(1) all alternatives are accepted,

(2) if you play an incorrect move then the computer will simply reply with a move that demonstrates that there was no checkmate after your first move.

Moreover, you can study the checkmate position by trying to make moves with the checkmated side. Then you will see arrows pointing to moves that would capture the king.

You can also move on a step further and try to solve puzzles where the task is to avoid getting mated on the next move. For example https://www.apronus.com/chess/puzzles/mate-in-1-avoid/?2vs1 has the same positions as the first link but now you play with the lone king to avoid mate.

More puzzles for beginners are listed on the table of contents at https://www.apronus.com/chess/puzzles/

那確實是將軍，我已經下象棋了幾個月了。

這一定是代碼（可能是問題）或客戶端或服務器（非常問題）的問題可能性不大，但情況可能如此）。您還可以學習其他國際象棋網站，例如 https://lichess.org/learn#/和 https://www.chess.com/lessons。

那些應該可以更好地工作，儘管它們仍然有一些問題，但這並不是太多。

The website (or that chess problem on that site specifically) is clearly buggy.
All 3 of the moves listed as correct answers are mates, and even shown with #
Qe7# Qc8# Qb8#

My guess as to what happened:

• The web site supports various different kinds of problems, including "one correct move".
• It doesn't have a chess engine checking for mates, just that they match some pre-programmed answers. It relies on humans to set up the correct-answer conditions separately from the question and answer text. (Introducing the possibility of human error causing this problem.)
• A human entered correct problem and answer text, but accidentally marked it as only the first answer being correct. Or some kind of syntax error or other mis-use of the problem-setting tools that made the website not understand that any of the answers were valid.

That would explain why all 3 listed moves have a # checkmate symbol after them: those are manually-entered text, and the web site doesn't truly know they're checkmates. Or doesn't know that they question is looking for checkmates, because programming that is separate from writing the text.

In future, if you encounter something online that seems to be telling you something that seems wrong, you can load up the position in a chess engine you trust and try it. Maybe you'll find there was a legal move you didn't spot.

As a beginner (or for any human) it's certainly possible to make mistakes. But this case is simple enough that it's pretty easy even for me (very much non-expert) to be pretty sure that all 3 of those moves are mates, and that there aren't any other mates. But it wouldn't take much more complexity for me to not be sure if a problem was buggy or if I was missing something.

In this case, the 3 listed moves that pop up being shown with # makes it fairly clear it's a bug, though.

雖然這裡每個人都正確，可以確保您是一個將死者，並且該工具是錯誤的，但我沒有看到他們解釋如何驗證這一點，並且由於您正在學習，這可能對您有用：

1. 由於白皇后可以在第八行的任意位置移動，因此白皇后確實可以控制黑國王
2. 黑皇沒有任何動作可以阻止。它有五種可能的移動方式，其中第二行到第八行，正如我們剛剛提到的，由白女王覆蓋，第三行到第七行，所有這些都由白國王覆蓋。
ol>

例如將女王移至D7或D8不會成為將軍。您能找出每種情況下的原因嗎？原因不同。

絕對是一個將軍。一定是計算機故障，或者是在問其他問題。也許是在要求僵持。或者它詢問您是否可以將其擴展到3個動作。只是為了伸展運動而已。而不是合而為一。

The highlighted "Qc8#" in your screenshot means, I think, that the displayed move is not the one you made but Qc8# (which means that the queen moves to the c8 square, effecting checkmate). You probably made a different move which is not shown in your screenshot.