I have added election_phragmen pallet in westend chain but the elections are still not taking place so i am facing an issue in adding validators. The validators i am adding remain in waiting state.In the logs there come an error of "Low connectivity - authority lookup failed for too many validators.
That warning is telling you that discovery is failing for at least 1/3 of validators. Which, depending on how many are you running this could be, 1 if the total number is 3.
This warning is coming from the networking layer, not the runtime. But if validators are not being discovered, or are not reachable, for whatever reason, then it might make sense that elections cannot happen if there are not validators to be elected. (Speaking form the top of my head here, so might not be 100% accurate)
Try checking how the network is configured, if there might be something avoiding this gossiping to happen between validators. Maybe firewalls, acls... whatever you might have in place. If that is not the case, launching the nodes again might help ? At least, to check if the scenario can be reproduced, or if the warning maintains over time.