Sometimes when a link is posted, ning automatically adds some garbage to the end of the hyper-link address and this corrupts the link - for example:

https://www.douglashistory.co.uk/history/Histories/douglas_tragedy....

which gives you:

To access the page, just remove the garbage from the end of the link in your browser (in this case it's %C2%A0) and then re-enter

Best regards