Exception on post... :-(

[michelep]

On a simple client.post() i got an exception:

Decoding stack results
0x40217044: _svfprintf_r at ../../../.././newlib/libc/stdio/nano-vfprintf.c line 641
0x40219f68: ethernet_output at netif/ethernet.c line 305
0x4021ffed: etharp_output_LWIP2 at core/ipv4/etharp.c line 893
0x4020d73d: EthernetClient::connect(char const*, unsigned short) at /packages/esp8266/hardware/esp8266/2.4.2/libraries/Ethernet/src/EthernetClient.cpp line 31
0x40100504: calloc at packages/esp8266/hardware/esp8266/2.4.2/cores/esp8266/umm_malloc/umm_malloc.c line 1680
0x4020cd71: RestClient::request(char const*, char const*, char const*, String*) at /arduino-restclient/RestClient.cpp line 114

Any hint ?