Exception(29) on ESP8266 using UniversalTelegrambot and EInk-Display

[pilexknolle]

Hello, I have been trying for a few days to operate an ESP8266 and an E-Ink display, with the goal of querying a Telegram bot and displaying the latest message on the E-Ink display. All the desired functions work in separate subprograms, but when I combine them, I get the Exception(29). After some research, it seems that this error indicates that something might be writing incorrectly to the memory or that the program is consuming too much memory. I am stuck at this point. Does anyone have any helpful tips on how to handle this?
Thank you

#include <ESP8266WiFi.h>
#include <WiFiClientSecure.h>
#include <UniversalTelegramBot.h>

// Wifi network station credentials
#define WIFI_SSID "name"
#define WIFI_PASSWORD "pw"
// Telegram BOT Token (Get from Botfather)
#define BOT_TOKEN "exampletoken"

#define ENABLE_GxEPD2_GFX 0

#include <GxEPD2_BW.h>
#include <Fonts/FreeMonoBold18pt7b.h>

#define GxEPD2_DISPLAY_CLASS GxEPD2_BW

static const uint8_t EPD_BUSY = D1;
static const uint8_t EPD_CS = D8;
static const uint8_t EPD_RST = D4;
static const uint8_t EPD_DC = D2;
static const uint8_t EPD_SCK = D5;
static const uint8_t EPD_MISO = -1;
static const uint8_t EPD_MOSI = D7;

#define GxEPD2_DRIVER_CLASS GxEPD2_420_GDEY042T81 // GDEY042T81 400x300, SSD1683 (no inking)

GxEPD2_BW<GxEPD2_DRIVER_CLASS, GxEPD2_DRIVER_CLASS::HEIGHT> display(GxEPD2_DRIVER_CLASS(/*CS=D8*/ EPD_CS, /*DC=D3*/ EPD_DC, /*RST=D4*/ EPD_RST, /*BUSY=D2*/ EPD_BUSY));



const unsigned long BOT_MTBS = 1000; // mean time between scan messages

X509List cert(TELEGRAM_CERTIFICATE_ROOT);
WiFiClientSecure secured_client;
UniversalTelegramBot bot(BOT_TOKEN, secured_client);
unsigned long bot_lasttime; // last time messages' scan has been done

const int ledPin = LED_BUILTIN;
int ledStatus = 0;

void handleNewMessages(int numNewMessages)
{
  Serial.print("handleNewMessages ");
  Serial.println(numNewMessages);

  for (int i = 0; i < numNewMessages; i++)
  {
    String chat_id = bot.messages[i].chat_id;
    String text = bot.messages[i].text;

    String from_name = bot.messages[i].from_name;
    if (from_name == "")
      from_name = "Guest";

   Serial.println(text);
   Serial.print(" von: ");
   Serial.print(from_name); 
   bot.sendMessage(chat_id, "Nachricht angekommen", "");
   printEINK(text);
  }
}


void setup()
{
  display.init(115200, true, 2, false);
  Serial.begin(115200);
  Serial.println();

  pinMode(ledPin, OUTPUT); // initialize digital ledPin as an output.
  delay(10);
  digitalWrite(ledPin, HIGH); // initialize pin as off (active LOW)

  // attempt to connect to Wifi network:
  configTime(0, 0, "pool.ntp.org");      // get UTC time via NTP
  secured_client.setTrustAnchors(&cert); // Add root certificate for api.telegram.org
  Serial.print("Connecting to Wifi SSID ");
  Serial.print(WIFI_SSID);
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED)
  {
    Serial.print(".");
    delay(500);
  }
  Serial.print("\nWiFi connected. IP address: ");
  Serial.println(WiFi.localIP());

  // Check NTP/Time, usually it is instantaneous and you can delete the code below.
  Serial.print("Retrieving time: ");
  time_t now = time(nullptr);
  while (now < 24 * 3600)
  {
    Serial.print(".");
    delay(100);
    now = time(nullptr);
  }
  Serial.println(now);
}

void loop()
{
  if (millis() - bot_lasttime > BOT_MTBS)
  {
    int numNewMessages = bot.getUpdates(bot.last_message_received + 1);

    while (numNewMessages)
    {
      Serial.println("got response");
      handleNewMessages(numNewMessages);
      numNewMessages = bot.getUpdates(bot.last_message_received + 1);
    }

    bot_lasttime = millis();
  }
}

void printEINK(String text)
{
  //char *output = text;

  display.setRotation(0);
  display.setFont(&FreeMonoBold18pt7b);
  display.setTextColor(GxEPD_BLACK);

  int16_t tbx, tby; uint16_t tbw, tbh;
  display.getTextBounds(text, 0, 0, &tbx, &tby, &tbw, &tbh);
  
  uint16_t x = ((display.width() - tbw) / 2) - tbx;
  uint16_t y = ((display.height() - tbh) / 2) - tby;
  
  display.setFullWindow();
  display.fillScreen(GxEPD_WHITE);
  display.setCursor(x, y);
  display.print(text);
  display.display(false);
}

Heres the shortend errormessage

Exception (29):
epc1=0x4000df64 epc2=0x00000000 epc3=0x00000000 excvaddr=0x00000000 depc=0x00000000

>>>stack>>>

ctx: sys
-----
--------------- CUT HERE FOR EXCEPTION DECODER ---------------

 ets Jan  8 2013,rst cause:2, boot mode:(3,6)

load 0x4010f000, len 3424, room 16 
tail 0
chksum 0x2e
load 0x3fff20b8, len 40, room 8 
tail 0
chksum 0x2b
csum 0x2b
v00067d20
~ld

[oldcurmudgeon]

Run the Esp Exception Decoder and post the results. This should show the path to the exception.