Helium joining problem with TTGO esp32 board

[ferrarid61]

Hello,
I'm a Helium lorawan network user. I was successfull using Helium whith Heltec Lorawan esp32 board using their sample code.
I'm tryng using your sample code with a TTGO ESP32 Lora32-oled board but the join session never ends
08947092: EV_JOIN_TXCOMPLETE: no JoinAccept
109395157: EV_TXSTART
109798405: EV_JOIN_TXCOMPLETE: no JoinAccept
109798645: EV_TXSTART
110180492: EV_JOIN_TXCOMPLETE: no JoinAccept
I'm in Italy at Milano in a quite well covered Helium area.
This is the code I'm using

https://github.com/mcci-catena/arduino-lmic/tree/master/examples/helium-otaa

Environment

• Version of LMIC 4.1.1
• Version of Arduino IDE being used: 2.1.0
• Network provider : Helium
• Region EU868
• Board : TTGO Lora32-Oled v2
• Radio SX1276