Arduino and ESP8266 not connecting to wifi hotspot

Hi,

I interfaced an esp8266 with arduino and used an external 3.3V power supply capable of supplying upto 700mA to power esp8266.

But i did not use a 3.3V regulator for TX and RX pins on arduino interface with esp8266,

Now esp powers on and everything, but does not connect to wifi.

Is this issue because i haven’t used the 3.3V regulator?

Here is my code…
ssid and no password.

#include <ESP8266wifi.h>
#include <WiFi.h>

char* ssid     = "abcd";
char* password = "";


void setup() {
  Serial.begin(115200);
  delay(100);

  // We start by connecting to a WiFi network

  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  
  WiFi.begin(ssid, password);
  
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");  
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

int value = 0;

void loop() {
  
  Serial.print("connecting to loop");
  }

It is working now,
as in esp8266 sends a ready message to my serial monitor upon powering on.
But none of the “AT” commands are working to check two way connection.

PFA.

What can be done?