The problem is unrelated to iPV6, i can assure because i have tested on the ipv6 and the method is an instantiation which does not connect to internet or doing networking task.
Based on your crashlog, my guess either
app.myID is nil at runtime.
Exception Type: EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000001, 0x000000010004a974
Termination Signal: Trace/BPT trap: 5
Termination Reason: Namespace SIGNAL, Code 0x5
Terminating Process: exc handler 
Triggered by Thread: 0
Anyway it is very important to know that what is SIGTRAP means. It is basically a run-time exception not an error. So if you cannot really find the issue you have to check that if there are any places which can course an exception. (specially with Swift optional types)