Sending AT commands to EESP8266 WIFI module

Good day everyone.

I have an ESP8266 wifi module. I have connected it to my system via USB to TTL converter and sending the AT commands through TeraTerm.

But i am not recieving a reply. I have tried with all the baud rates and no reply.
The connections are as follows:

ESP8266----------------------Connections
VCC--------------------------- 3.3V of external supply
GND-------------------------- GND of external supply
CH_PD------------------------3.3V of external supply
RX---------------------------- TX of USB to TTL converter
TX----------------------------RX of USB to TTL converter

What might be the issue?

Thank you.

Using MAX232 resolved the issue.