blynk.email sometimes not working, while blynk notification is work

I have tested the below code for whole morning, and the code can sent out the emails successfully and no missing.
However, since 3 pm, there is no any emails sent out, but the notification can be sent out and serial monitor show that the program is operating normally.

I have also tried to change another email (company email or Gmail), both are not success, even I changed another board and re-upload the program.

My board is ESP8266 NodeMCU

#define BLYNK_PRINT Serial

//#define BLYNK_MAX_SENDBYTES 128

#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>


char auth[] = "";

char ssid[] = "";
char pass[] = "";

const String SiteNo = "XXX";

volatile byte bFlag1; //Status of air blower 1
volatile byte bFlag2; //Status of air blower 2
volatile byte bFlag; //Status of whole system
BlynkTimer timer;

void setup()
{
  // Debug console
  Serial.begin(115200);
  Blynk.begin(auth, ssid, pass);
  Blynk.email("xxx@gmail.com", String(SiteNo) + "Online", "My Blynk project is online.");
  Blynk.notify(String(SiteNo) + " online");
  pinMode(14, INPUT); //Initial is 0V
  pinMode(12, INPUT); //Initial is 0V
  attachInterrupt(digitalPinToInterrupt(14), email_B1, CHANGE);
  attachInterrupt(digitalPinToInterrupt(12), email_B2, CHANGE);
  timer.setInterval(20000L, system_status);
}
void email_B1()
{
  int B1Fault = digitalRead(14); //Air Blower No.1
  if (B1Fault == HIGH) //if this pin is 3.3V
    bFlag1 |= 0x01; //this byte changes to 0000 0001
   else if
    (B1Fault == LOW)
    bFlag1 = 0x00; //if this pin is 0v, changes to 0000 0000
  
}

void email_B2()
{
  int B2Fault = digitalRead(12); //Air Blower No.2
  if (B2Fault == HIGH) //if this pin is 3.3V
    bFlag2 |= 0x02; //this byte changes to 0000 0010
   else if
   (B2Fault == LOW)
    bFlag2 = 0x00; //if this pin is 0v, changes to 0000 0000
  
}

void system_status()
{
   Blynk.email("xxx@gmail.com", String(SiteNo), bFlag);
   Blynk.notify(String(SiteNo) + " alarm sent");
   Serial.println(String(SiteNo));
   Serial.println(bFlag, BIN);
   

}

void loop()
{
  Blynk.run();
  timer.run();
  bFlag = bFlag1 |= bFlag2;
  
}

User is limited with 100 messages per day in the Blynk Cloud;

Just saw this definition for blynk email.
And I have already sent out 100 messages today, so I can't send email by today.

Any method to break this limitations?