I have a problem that no bacteria bands appear, although I previously replaced the master mix, nuclease free water, and even used new primers, but the result is the same as in the pictures. Note that I took a PCR device to another lab to make sure, and it was fine and gave results. When I used it in my lab, it did not give results, as in the pictures. By the way, I tested the DNA genome only by electrophoresis, and the results were good, but after amplification by PCR, the results were as in the pictures every time, and I even used RNase to no avail.