Pink Tiles

Hi,

I have set up my own tile server and whenI access slippymap.html on that server, map tiles are displayed correctly.

But, if I copy same slippymap.html to other web server and try to load it from that server, I see only pink tiles.
Why?

Can somebody help me here?

Maybe you can find a solution via https://help.openstreetmap.org by searching there for “pink”