Connect two esp8266 by swap uart

I MADE PROJECT BASE ON esp mesh hens esp mesh forbidden send data to HTML by the browser so I use UART0 TO send data from mesh to esp8266
I do code for send receive but it did not work it just send
؟؟؟؟

// revived side
String resive  ;
String commant = " ";
void setup() {
 Serial.begin(115200);
 pinMode(15, OUTPUT);
pinMode(13, INPUT);
}

void loop() {
  Serial.flush();
 Serial.swap();

 resive  = Serial.readString( );//by swap uart from mesh gateway

 Serial.swap();//normal uart

 Serial.print("\nfrom ---->  ");
 Serial.print(resive);
}
//send side
String commant = " ";
int count ;
void setup() {
  // put your setup code here, to run once:
Serial.begin(115200);
pinMode(15, OUTPUT);
Serial.swap() ;
}

void loop() {
  
 // while(Serial.available()){
   Serial.write("\n234f\n ");
 // }
}

help me please