ember cli url not working on server with manual return key (versus link-to)

An ember cli site was deployed onto a server and it works fine. Links via {{link-to}} all work beautifully.

BUT, when a user (me that is) manually enters a url and hits return. then the site is not found.

The resource you are looking for has been removed, had its name changed, or is temporarily unavailable.

even changing a parameter of a working url (initially navigated to thru link-to)

http://site/start/0/length/30

and simply backspacing, changing the 30 to 20 and hit return

http://site/start/0/length/20

its a no go

localhost:4200 doesn't have this issue.

has anyone observed this vicious behaviour.

i actually need it for a callback redirect for oauth. but then noticed than any manually entered urls dont function.