ICE -> FreeSWITCH tries exclusively the first candidate

Hi, currently I have the problem that the FreeSWITCH only serves the first candidate from the candidate list via STUN request. I expected it to try to reach all candidates relatively soon (trickle). In the source code I saw that there are four ICE types: ICE_GOOGLE_JINGLE ICE_VANILLA ICE_CONTROLLED ICE_LITE What is behind them, and how can I select them from the "outside"? Or am I on the wrong track? What to do, that the FreeSwitch serves the candidates according to Trickle? I have the same result for mod_sofia and mod_verto (is clear, they use the same media stack). Thanks and greetings Alex