For example, an extra character is a slash at the end of the address of the page you need.
This is the case when an error occurs:

https://www.facebook.com/UKRAINEDEF/
And this is the correct way to write it:

https://www.facebook.com/UKRAINEDEF
If the link is fine, please check your settings in the Connections section. To do this, go to Settings and select the Connections item.