Hi Amran,
Earlier this summer, Mapquest discontinued the mapping service used by Kibana.
See that issue here https://github.com/elastic/kibana/issues/7717, and earlier discussion here Map visualizations have stopped working due to MapQuest change July 11, 2016.
Elastic is now hosting its own service, but with fewer zoom levels. That's what you're seeing in 4.5.4. You can still configure Kibana to use another mapping service (if you have access to one) using the advanced settings.