Soft watchdog randomly occurs

[ipa64]

Hello,
Sometimes at the second messages sent, sometimes at the fourth or more I got a software watchdog reset on my esp8266 Wemos D1 mini.
I don't know if I should provide other information.
And why this in the log at ??:? we should expect an address, no ?

Thank you, have a nice day

UniversalTelegramBot 1.3.0

--------------- CUT HERE FOR EXCEPTION DECODER ---------------

Soft WDT reset

Exception (4):
epc1=0x40221598 epc2=0x00000000 epc3=0x00000000 excvaddr=0x00000000 depc=0x00000000

Level1Interrupt: Level-1 interrupt as indicated by set level-1 bits in the INTERRUPT register
epc1=0x40221598 in lwip_strnicmp at /local/users/gauchard/arduino/arduino_esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/core/def.c:164

stack>>>

ctx: cont
sp: 3ffffc40 end: 3fffffd0 offset: 0160
3ffffda0: 40206178 3fff3044 00000090 3ffefcc8
3ffffdb0: 3ffefc38 3ffefc38 00000020 401010a4
3ffffdc0: 0003921b 3ffffeb4 0000000c 00002710
3ffffdd0: 3ffffe28 3fff3044 3ffe8fe5 402061ed
3ffffde0: 402100f4 ffffffff 3ffffe00 0000002e
3ffffdf0: 00000000 00000040 00000020 401010a4
3ffffe00: 00000031 00000040 3ffffe90 3ffffe90
3ffffe10: 000001bb 3ffe8fe5 3fff0b4c 4020810a
3ffffe20: 4025ee5c 3ffffeb4 402100f4 00000000
3ffffe30: 3fffff10 3ffffeb4 3ffef140 40203a81
3ffffe40: 00000032 00000001 3ffffe90 00000000
3ffffe50: 3fff2994 00000000 3ffffe9c 00000000
3ffffe60: 3fffff10 3ffffef8 3fffff10 00000000
3ffffe70: 3ffef140 3ffffe9c 3ffffe90 00000000
3ffffe80: 0003921b 00000001 3ffef140 40203bcc
3ffffe90: 3fff2994 003d003f 83000000 3fff297c
3ffffea0: 000b000f 80000000 3ffef5d8 00000030
3ffffeb0: 00000004 00000000 3fff3690 00000000
3ffffec0: 3fffff10 3ffffef8 00000020 3fffff78
3ffffed0: 3ffe900b 3ffffef8 3ffe9052 3fffff78
3ffffee0: 3fffff60 3ffef140 00000000 40203cf1
3ffffef0: 00000003 3ffef2c0 3fff30d4 3fff30f1
3fffff00: 3fff3690 3fff36b0 00000000 3fffff90
3fffff10: 3fff36a0 3fff3690 3fffff20 4020a3b7 <
3fffff20: 3fffff10 3ffffef8 3fffff84 4020a6b2
3fffff30: 3fffff6c 3ffe89f1 3ffef520 3ffef391
3fffff40: 3ffef520 00000000 3fffff60 3ffef391
3fffff50: 3ffef520 3ffef2c0 3ffe863c 40201d05
3fffff60: 00000000 00110000 00000000 38333531
3fffff70: 33313332 0a003134 3fff2864 0011001f
3fffff80: 83000000 00000000 0011001f 00000000
3fffff90: 00000000 0010001f 00000000 3ffef5d8
3fffffa0: 3fffdad0 00000000 3ffef5ac 3ffef5d8
3fffffb0: 3fffdad0 00000000 3ffef5ac 4020b450
3fffffc0: feefeffe feefeffe 3fffdab0 40101419
<<<stack<<<

0x40206178 in _dns_found_callback(char const*, ip4_addr const*, void*) at ESP8266WiFiGeneric.cpp:?
0x401010a4 in malloc at ??:?
0x402061ed in _ZL14hostByNameImplPKcR9IPAddressj14DNSResolveType$part$0 at ESP8266WiFiGeneric.cpp:?
0x402100f4 in DhcpServer::isRunning() const at ??:?
0x401010a4 in malloc at ??:?
0x4020810a in BearSSL::WiFiClientSecureCtx::connect(char const*, unsigned short) at ??:?
0x4025ee5c in etharp_output at ??:?
0x402100f4 in DhcpServer::isRunning() const at ??:?
0x40203a81 in UniversalTelegramBot::sendPostToTelegram(String const&, ArduinoJson::V6213PB2::JsonObject) at ??:?
0x40203bcc in UniversalTelegramBot::sendPostMessage(ArduinoJson::V6213PB2::JsonObject, bool) at ??:?
0x40203cf1 in UniversalTelegramBot::sendMessage(String const&, String const&, String const&, int) at ??:?
0x4020a6b2 in String::concat(char const*, unsigned int) at ??:?
0x40201d05 in loop at ??:?
0x4020b450 in loop_wrapper() at core_esp8266_main.cpp:?
0x40101419 in cont_wrapper at ??:?

--------------- CUT HERE FOR EXCEPTION DECODER ---------------

Here includes libraries

#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>
#include <WiFiClientSecure.h>
#include <UniversalTelegramBot.h>
#include <ArduinoJson.h>
#include <UrlEncode.h>
#include <ESP8266TimerInterrupt.h>
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>