Change name and password of HC-05

Hello, I am a beginner of Arduino and these stuff, i want to change the name and password of HC-05 to make it secure and i take help with this website , but when i hold the button and then connect the connector, the LED start blinking but it never stops after 2-3 sec nor getting "ok" message from Serial monitor while typing "AT" and following every instruction fully. Please help me find the solution.

Incoherent but, if you are indeed following every instruction fully, I think the best guess is that you have an erratic power connection, thereby having HC-05 accidentally falling out of AT mode.

When in AT mode, the LED flashes about once every two seconds, if you saw the flash at about 2Hz, you were never in AT mode in the first place.