Error when build

[helmuteke]

hello ,

i did the steps more then 5 times but receive always same error when i build.

`AR build/lwip/liblwip.a
CC build/main/voip_app.o
/home/helmut/espwork/sip_phone_example/main/voip_app.c: In function '_sip_event_handler':
/home/helmut/espwork/sip_phone_example/main/voip_app.c:335:14: error: 'SIP_EVENT_BUSY' undeclared (first use in this function)
case SIP_EVENT_BUSY:
^
/home/helmut/espwork/sip_phone_example/main/voip_app.c:335:14: note: each undeclared identifier is reported only once for each function it appears in
/home/helmut/espwork/sip_phone_example/main/voip_app.c: In function 'app_main':
/home/helmut/espwork/sip_phone_example/main/voip_app.c:517:14: warning: unused variable 'tver' [-Wunused-variable]
uint32_t tver = stmpe610_getID();

`

Some a idea ?