When you specified more than 4 servers in set::timesynch::server you could

experience weird issues such as a flood of 'Cannot accept connections:
invalid argument' messages. Reported by hyper_threader (#4242).

src/timesynch.c

@@ -184,6 +184,8 @@ int succesfully_sent = 0;
 
 		set_non_blocking(s[n], &me);
 		n++;
+		if (n == MAXTIMESERVERS)
+		        break;
 	}
 	numservers = n;