Steps to reproduce
Steps to reproduce the behavior:

• open examples page https://leafletjs.com/examples/wms/wms.html

Expected behavior
demos display wms layers on the map

Current behavior
demos does not display wms layers on the map

Environment

• Leaflet version: 1.5
• Browser (with version): chrome 78, firefox 70
• OS/Platform (with version): manjaro

Additional context
seems that used wms services are down

Minimal example reproducing the issue
https://leafletjs.com/examples/wms/wms.html