Well, I cannot see your current code.
At the very least, add logging when an error occurs using an external API. You should not need to use a debugger to diagnose such errors. When a connection fails on another user's machine, they may not have a debugger or the skills required to effectively use one. Something not unlike this:
int result = SomeLib_DoStuff(/* ... */);
if(result != SOME_LIB_STUFF_DONE) {
std::stringstream error;
error << "DoStuff returned failure code: " << result << ", error message: " << SomeLib_GetError();
log(error.str());
return false;
}