The gpio pin connection seems to be correct. After all, when I connect the 5V relay to the 3.3V voltage, it works! What could be the cause?
When measuring the 5v of the Raspberry Pi board with the tester, it seems that about 4.0v and 3.3v are about 2v output.
The reason the color of the wires is different is that I connected two wires by soldering them in succession. It is connected to gnd.
The problem is that the 5V relay doesn't work for 5V and I don't know if it works for 3.3V.
Let's test it with another new tester ....I will also change to a genuine Raspberry Pi adapter.